At Weather Applied Metrics (WAM), we help teams, broadcasters, analysts, and fans understand how weather impacts the games we love. We specialize in turning complex atmospheric dynamics into engaging sport-specific insights. Our work sits at the intersection of meteorology, aerodynamics, applied physics, and sports analytics — enabling players, teams, leagues, sportsbooks, broadcasters, and fans to account for weather as a measurable, modelable variable in performance.

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Weather introduces variability. But variability is not randomness — it’s physics… and it can be measured, modeled, and even predicted. WAM’s mission is to make these effects visible, explainable, and actionable.

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What We Do

Wind, temperature, humidity, and pressure don’t just describe the environment — they alter the trajectory, speed, and spin of the ball as well as the outcome of plays, games, and even seasons. Using sophisticated weather sensors at stadiums and venues, we are able to measure and quantify atmospheric conditions in real time. This data is integrated with a 3D “digital twin” of each venue using Computational Fluid Dynamics (CFD) models to reveal how wind and airflow interacts with the ball — and the game.

Our Expertise:

• High-resolution wind and weather models, tailored to sports performance, broadcast, and analytics
• Custom CFD (Computational Fluid Dynamics) simulations to analyze airflow in and around stadiums and venues
• Real-time ball flight impact metrics for broadcast, live betting, and tactical decision-making
• Predictive modeling tools for pregame strategy, betting markets, and scenario planning
• Historical reconstructions that isolate the impact of weather on performance and outcomes

Our data has been integrated into NFL, MLB, and ATP live broadcasts, and is utilized for advanced team analytics, professional golf coverage, and proprietary sports modeling systems.

Why It Matters

Contrary to common belief, it isn’t possible to accurately gauge the impact of weather by simply checking the local forecast or looking at flags flying near the stadium. Every venue contains a unique, invisible microclimate — shaped by its architecture, surrounding structures, and local terrain — that standard forecasts cannot capture.

From a baseball carried 12 feet farther on a hot, humid afternoon… To a golf shot knocked off line by a shifting crosswind… To swirling stadium winds enhancing the topspin on a late-match serve… Weather introduces variability. But variability is not randomness — it’s physics… and it can be measured, modeled, and even predicted.

Who We Are

WAM was founded by experts in atmospheric science, engineering, and sports analytics, with deep experience in real-time modeling and simulation. Our interdisciplinary approach ensures that our data provides engaging and useful sport-specific insights and storylines — not just abstract forecasts or weather station data.

Our team consists of physicists, engineers, meteorologists, sports scientists, and former professional athletes. Together we aim to measure and understand how weather influences player evaluation, performance, and outcomes.

We collaborate with professional sports teams, leagues, tech partners, networks, and broadcast teams to translate complex environmental interactions into valuable information that can be leveraged — on the field, in the booth, or behind the models.

What’s Next

This blog will serve as a place to share what we’re learning, highlight interesting case studies, and explain the science behind our work. We’ll explore airflow around stadium structures, the interplay of spin and wind, and how even subtle shifts in weather can shape performance in measurable ways.

Whether you’re a data analyst, broadcaster, coach, or simply curious — we invite you to follow along. Because when the wind plays a role, you should be able to #playthewind.

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Understanding how weather shapes performance starts with a clear framework for testing it. Having established the core methods previously, where we explained how we use physics-based modeling to isolate the effects of temperature, pressure, humidity, and altitude on ball flight, we can now explore how those principles play out in baseball. Here we apply that framework through a set of controlled simulations to see how changes in the atmosphere can influence the way the game is played.

The idea is simple: keep the launch conditions the same, adjust one weather variable at a time, and see how the results change.

As a quick reminder, for this and similar analyses we are focusing only on atmospheric conditions that impact air density. Wind is not included, as it introduces a separate layer of complexity that we will address in future explorations.

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The most obvious starting point in baseball is to look at how atmospheric variables impact a home run-like fly ball. Even a few inches of impact to distance can be the difference between a multi-run homer and an inning-ending out, significantly impacting game outcomes. The launch parameters we will use for this simulation would have the ball just barely clear the top of the center field fence of our digital stadium in standardized conditions. This allows us to more directly interpret the impact of atmospheric conditions on whether this hit would be a home run (or not) in the given conditions!

Temperature

As we see above, the same home run-like fly ball hit in 55° weather travels about 10 feet farther when the temperature rises to 80°. Many fly balls fall within that margin of the outfield wall, so temperature-driven changes in air density can alter home run rates and game outcomes significantly. This is because air becomes less dense and offers less drag to a moving baseball as it warms. For a home run-like fly ball, we see about a 4 ft increase in distance for every increase of 10°F. 

Many baseball fans are familiar with the work of baseball physicist Alan Nathan, whose research established the widely cited rule of thumb that a 10° rise in temperature increases a typical fly ball by 3 feet (3.3 ft). Our findings align with those results. In the above simulation, our home run-like ball gains closer to 4 feet (3.8 ft), while instead simulating with the parameters of a typical fly ball results similarly in an increase of about 3.3 feet per 10°. 

The plot below utilizes average hit parameters from MLB data and similarly shows roughly a 3 ft gain per 10° increase in temperature. The values change slightly, but the underlying principle is simple: The longer the ball stays in the air, the more temperature and other atmospheric variables can influence its flight.

Rough Rule of Thumb: Home run-like fly ball distance increases by about 4 feet for every 10°.

Rough Rule of Thumb: Average fly ball distance increases by about 3 feet for every 10°.

Altitude

Decreases in air density related to altitude are actually a result of the decreased pressure that occurs at higher altitudes. In the visual above, you can see the red line comparing how our fly ball distance changes relative to altitude. The light blue line is there to also visualize the relationship between altitude and atmospheric pressure. In our altitude-based simulations, this hit would fly more than 30 feet farther at an altitude of 5,280 feet (1 mile) than the same hit at sea level!

Rough Rule of Thumb: Home run-like fly ball distance increases by about 6 feet for every 1,000 feet of altitude.

Atmospheric Pressure

At a constant altitude, atmospheric pressure changes gradually as large-scale weather systems move through. In this simulation, we modeled the difference between a strong high-pressure system (around 30.40 inHg) and a deep low-pressure system (around 29.30 inHg), a range that captures the stronger end of normal weather-related pressure changes for a single location.

Our results show that such a change can add roughly 7 feet of distance to a home run-like fly ball. A shift of this magnitude (about 1 inHg) usually unfolds over several days, while smaller variations of around 0.3 inHg are far more typical from day to day.

Rough Rule of Thumb: Home run-like fly ball distance increases by about 2 feet for every 0.3 inHg drop in pressure.

Relative Humidity

The impact of relative humidity on a ball in flight is subtle and often misunderstood. Since water vapor molecules are lighter than dry air molecules, humid air is actually less dense, which slightly reduces air resistance. In our simulations, moving from 0 percent to 100 percent relative humidity increases carry distance by only about 2 feet. That effect is real, although small compared to other atmospheric factors.

In real game conditions, humidity influences more than just air density. Moisture can be absorbed into the baseball. This can slightly increase the ball’s mass and affect its elasticity, which affects both batted-ball speed and how the ball carries. These physical changes can offset the aerodynamic benefit. As a result, higher humidity can shorten flight distance rather than increase it in practice. MLB mandates humidors for all teams to standardize baseball moisture content and keep ball performance more consistent.

But because humidity can alter the ball itself and its air-density effect is small, the net impact is subtle and hard to isolate in real game conditions. Utilize this rule of thumb accordingly. 

Rough Rule of Thumb: Home run-like fly ball distance increases by about 1 foot for every 50% increase in humidity.

Pitches and Other Hit Types

While this analysis focuses on a home run-like fly ball, atmospheric effects extend to all batted and pitched balls. Pitches can be especially sensitive to air density due to spin, which can influence pitch movement through changes in drag and lift. Line drives and pop-ups experience different aerodynamic forces based on spin and launch angle, though generally speaking the longer the ball is in the air, the greater impact atmospheric variables can have.

Summary

The takeaway is simple: the atmosphere always plays a role, even when it’s invisible.

Join us as we explore how weather and physics influence performance across different sports! Visit Modeling the Impact of the Atmosphere on Sport: Setting the Stage, where we discuss the methodology of these simulations and will link to other sport- and play-specific analyses as they become available.

Rule of Thumb Cheat Sheet

For home run-like fly balls:

• Warmer air: +4 ft per 10° rise (+3 ft for average fly ball)
• Higher altitude: +6 ft per 1,000 ft
• Lower pressure: +2 ft per 0.3 inHg drop
• More humidity: +1 ft per 50% rise

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Translating atmospheric science into practical sport-relevant stories and information requires real-world data, advanced simulation, and physics-based modeling. This article explores how specific weather conditions influence gameplay across different sports, leveraging our own technology to provide quantifiable insights into just how much, or how little, atmospheric variability can actually impact the sports we love to watch and play.

Weather Applied Metrics

While modern ball-tracking systems accurately capture trajectory, they do not inherently distinguish the underlying forces shaping it. Variables such as wind, spin, pressure, temperature, and humidity each exert distinct aerodynamic influences on the ball’s flight. Isolating and quantifying the individual contributions of these factors is complex, yet essential, as the observed path is the result of their combined and often nonlinear interactions.

This is the kind of complexity Weather Applied Metrics aims to better understand. By modeling how atmospheric factors influence ball flight, we seek to make visible the invisible forces at work in ways that ball-tracking data alone cannot reveal. Through physics-based simulation and detailed weather inputs, we help shed light on patterns and storylines that are often hidden in plain sight.

Relative Impact of Atmospheric Variables

We’ve previously laid the foundation for understanding the basic physics of sports aerodynamics, as well as a theoretical understanding of the primary mechanisms that cause atmospheric variables to alter air density, influencing the flight of the ball. Based on this foundation and the supporting evidence, we can broadly classify the potential impact of different atmospheric variables on ball flight:

Interdependence of Atmospheric Conditions

These variables aren’t truly independent. Temperature influences pressure and humidity, altitude alters pressure, and pressure affects how much moisture air can hold. The combined effect of these factors makes modeling crucial to untangling their true impact on gameplay. With the right tools, weather goes from unpredictable to understandable.

Model Insights in Action

By using our patented technology and physics-based modeling tools, we can run simulations and adjust key atmospheric variables one at a time to better understand how each element of weather affects the game. This analysis isn’t about measuring the exact impact of weather on a specific play, instead we are running experiments to explore each condition in isolation. The results should both help confirm patterns seen in real-world data and offer clear, useful takeaways about how atmospheric conditions shape performance.

The flight of the ball reflects the intertwined and often nonlinear effects of wind, spin, altitude, temperature, humidity, and pressure, making modeling essential to isolate their true impact on gameplay.

Brief Methodology and Approach

Here we simulate a series of ball flight trajectories using standardized parameters in a hypothetical digital environment representing real-world geometry and atmosphere of a sporting stadium or venue. For each play type, ball launch parameters will stay constant, while we systematically adjust the pressure, humidity, temperature, and altitude of the environment to see how each factor influences ball flight.

Finally, we will plot the atmospheric parameter of interest against the overall outcome of the ball’s flight, in most cases distance, to provide a visual reference of the impact. We will use this set of standardized atmospheric conditions as our baseline of comparison:

• Temperature: 72°
• Relative Humidity: 55%
• Altitude: 0 ft (sea level)
• Atmospheric Pressure: 29.92 inHg

A Note on Hits and Bounces…

This analysis focuses exclusively on how atmospheric conditions affect the ball’s flight through the air, not how they influence contact dynamics such as how the ball is struck, bounces, or rolls. Those interactions depend on surface properties, impact angles, spin transfer, and material deformation, each of which introduces its own layer of complexity. While these factors are outside the scope of this study, they play a crucial role in the full picture of weather-and-sport interactions.

Making the Invisible Visible

Weather impacts are often overlooked or misunderstood in sports analysis, but as we’ll explore, they can in some cases be game-changing. With precise modeling and standardized inputs, these atmospheric variables can be quantified and communicated, helping turn hidden environmental forces into insights that benefit athletes and analysts, as well as broadcasters explaining in-game dynamics and sports bettors seeking an edge in changing conditions.

Over the coming weeks, we’ll publish and link new posts in this series highlighting simulation results and breaking down how temperature, humidity, pressure, and altitude influence your favorite sport.

Sports-Specific Results:

• Baseball – The Home Run Ball
• Football
• Golf
• Tennis

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Weather plays a defining role in shaping the behavior of the air, and by extension, how a ball travels through it. While the physics of drag and spin are universal, the environment in which they act is anything but. This article unpacks how temperature, humidity, pressure, and altitude work individually and together to influence air density and the resulting ball flight in sports.

Atmospheric conditions don’t just shape the field… they shape the physics.

Temperature

One of the most commonly referenced weather-stats we hear, from the great work of Dr. Alan Nathan, is that an increase in 10°F can add approximately 3 feet of distance to a fly ball.

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Higher Temperatures = Lower Air Density

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There is less drag (air resistance) in warmer air, because the air molecules are more spread out; reducing air density and “boosting” ball flight distances. While warmer temperatures don’t make fastballs faster, pitches will better retain their velocity from the initial release, resulting in a higher velocity at the plate when compared to colder conditions (all other things equal). Respected golf instructor Andrew Rice found with TrackMan data that when temperatures rise about 10°F from morning to afternoon (which happens on most days) the ball carries roughly 2 yards farther.

Humidity

While you may often hear wet, humid weather described as “heavy”, counterintuitively, humid air is less dense than dry air. This is because water vapor molecules actually weigh less than the oxygen or nitrogen molecules they replace. The impact, however, is relatively small.

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Higher Humidity = Lower Air Density

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In coastal regions, dense marine layers can further complicate things by layering cool, humid air near the surface and subtly altering both air density and ball behavior in ways that aren’t always intuitive.

Moisture in the Mix

In sports like tennis and baseball, the balls themselves can absorb moisture from humid environments, making them heavier and altering their aerodynamics and their response to impact. This can have a significantly greater impact on ball flight compared to humidity’s influence on air density and drag. In contrast, golf balls are built with impermeable covers, preventing significant moisture absorption and maintaining consistent behavior regardless of humidity.

Recognizing how important this is, Major League Baseball now requires all teams to store baseballs in humidors, ensuring that moisture content, and therefore ball performance, remains consistent across different parks.

Atmospheric Pressure and Altitude

Altitude is one of the most recognized factors in sports performance because of its large impact. The effect comes mainly from the drop in atmospheric pressure that occurs with elevation which lowers air density. Atmospheric pressure itself is shaped by both altitude (the amount of atmosphere above you) and, to a smaller extent, large-scale weather systems. Low-pressure environments reduce air density, while high-pressure systems increase it.

In Denver, at roughly one mile above sea level, air density drops to about 82% of sea-level conditions. According to Titleist, this results in approximately a 6% increase in distance with your driver. At Coors Field, fly balls travel 5–10% farther and pitches show less movement due to Magnus effects, leading to increased home run totals. To try and counteract this effect, Coors Field has some of the furthest fences of any MLB park!

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Higher Altitude = Lower Air Density

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Atmospheric pressure changes independent of altitude are usually gradual and relatively small compared to the dramatic drop caused by increasing elevation. However, shifts between low- and high-pressure zones can still influence weather conditions, with low-pressure systems bringing rising air, clouds, and instability, and high-pressure systems leading to sinking air, clear skies, and more stable conditions.

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Lower Atmospheric Pressure = Lower Air Density

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Sport-Specific (Ball) Considerations

In golf, atmospheric pressure impacts the ball’s flight through changes in air density but does not alter the ball’s internal pressure, since golf balls are solid and sealed.

In other sports like football, however, external atmospheric pressure can affect the internal pressure of the ball itself, which is why the NFL strictly regulates football inflation between 12.5 and 13.5 psi, a standard that became widely known during the “Deflategate” controversy.

In tennis, ball pressure is not actively regulated during matches, meaning that external pressure and altitude can cause noticeable differences in ball behavior. To address this, the International Tennis Federation (ITF) mandates the use of special high-altitude balls at tournaments held above 4,000 feet.

These pressure differences have minimal impact once a ball is in flight, but can significantly affect how the ball compresses and rebounds, influencing bounce, “feel,” and energy transfer when struck or contacting a surface.

How Atmosphere Alters Outcomes

Weather’s influence on air density provides a scientifically grounded explanation for why the same swing, serve, or throw might produce vastly different outcomes in different conditions. These environmental factors don’t just change the feel of the game, they change the physics, and in doing so, influence decisions made by players, coaches, analysts, broadcasters, and even fans.

Key Takeaways:

• Higher temperatures lower air density, allowing balls to travel farther and better retain speed.
• Humidity reduces air density slightly, but can affect ball mass and elasticity depending on the sport.
• Higher altitudes and lower pressures significantly decrease air density, increasing carry distance and reducing movement on pitched or spinning balls.
• Sport-specific equipment can respond differently to changes in atmospheric variables, with many professional sports organizations having introduced regulations to manage.

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Analyzing the aerodynamics of sports and ball flight requires a foundational understanding of the physical forces acting on them in real-world environments. This article introduces the foundational science behind how weather affects ball flight through drag, spin, and fluid dynamics—laying the groundwork for a deeper understanding of the atmospheric effects on sports for coaches, athletes, analysts, broadcasters, and fans alike.

Drag, Magnus Effect, Boundary Layers

In basic physics, we learn Newton’s Laws of Motion: for the flight of a ball, there is an initial speed and angle, impacted only by the force of gravity pulling the ball downward forming a perfect parabolic arc. Newtonian mechanics tells us that any ball hit, kicked, or thrown at the same speed and angle should land in the same spot…

However, in the real world, atmospheric elements introduce aerodynamic forces like drag and the Magnus effect that significantly alter that parabolic trajectory.

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At the core of ball flight physics are two key aerodynamic forces: drag and the Magnus effect.

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These real-world effects, first studied by 19th-century scientists like Gustav Magnus, Navier, and Stokes, and later by researchers such as Dr. Alan Nathan and golf physicist Dr. Alastair Cochran, explain why actual ball flight can look so different from theoretical examples.

Understanding Drag

Drag is the aerodynamic force that resists a ball’s motion through the air — commonly known as air resistance. It depends on factors like air density and ball speed, surface texture, and shape. In real-world conditions, smoother and faster-moving balls experience increased drag. Rough features like golf ball dimples intentionally disrupt the boundary layer to reduce drag and help the ball travel farther.

The Magnus Effect and Spin-Induced Movement

The Magnus effect is the aerodynamic force that causes a spinning ball to curve, lift, or dive by creating pressure differences around it. The Magnus force is always perpendicular to the ball’s path and pushes in the direction that the front of the ball is spinning as it moves through the air. 

Another way to conceptualize this is to imagine the ball spinning through the air and shedding air parcels in the direction opposite to the spin — similar to how a balloon zips around the room when released without being tied off. The expelled air acts like thrust in one direction, causing the ball to accelerate in the opposite. A backspinning ball (below), for example, pushes air downward (blue arrow) in its wake, which in turn creates an upward force (red arrow) that helps the ball stay aloft longer.

The Magnus force is what causes the curving motion we see in tennis topspin serves, baseball curveballs, and bending soccer free kicks, as it pushes the ball in the direction of its spin. The strength of the Magnus Effect depends on spin rate, velocity, and again air density; meaning weather conditions can noticeably alter how much a ball dips, bends, or lifts.

Boundary Layers and Seam Effects

Other secondary aerodynamic effects include boundary layer behavior, where a thin layer of air clings to the ball’s surface and is influenced by surface roughness. Seam effects specific to baseball can also occur, where the orientation of the seams creates asymmetric airflow that can add unpredictable movement to a pitch.

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Air isn’t empty — it’s a dense fluid whose properties define how objects travel, spin, and move.

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Air as a Playing Field

Because air is a fluid, its properties — including temperature, humidity, and pressure — directly affect its density and behavior, meaning that even small changes in the environment can alter the forces acting on the ball and ultimately influence how far, how fast, and how much the ball curves through the air.

Understanding Air Density

Air density is the mass of air per unit volume. It’s the composite variable influenced by temperature, humidity, pressure, and altitude. Each of these different atmospheric components contribute more or less to air density, and it’s the summation of these factors that directly impact what we experience. In a nutshell…

• Lower air density reduces both drag and Magnus forces: balls travel farther, better maintain velocity, but curve less due to Magnus effects.
• Higher air density increases both drag and Magnus forces: balls don’t travel as far, slow quicker, and exhibit more movement due to Magnus effects.

The same throw, hit, swing, pitch, or serve can yield radically different outcomes purely based on air density!

Why Weather Is a Player

The forces of drag, spin, and surface interaction shape every ball’s trajectory. While these forces originate in physics, their real-world impact is constantly shaped by the environment. And at the heart of all of it lies air density — the fluid playing field in which games are won and lost!

Key Takeaways:

• Air isn’t empty — it’s a dense fluid whose properties, especially air density, define how balls travel, spin, and move through space.
• Aerodynamic forces like drag and the Magnus effect respond directly to environmental changes, meaning the same action can yield different outcomes depending on weather conditions.

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