How to play tennis in wind, sun, heat and altitude

Read the air before the warm-up. Adjust before it beats you.

Key facts

~1.21kg
Standard air density is about 1.21 kg/m³ and a tennis ball's free-flight drag coefficient is about 0.507. At altitude the air is thinner, so drag falls and the ball flies further.
Tennis Warehouse University: tennis ball trajectories, drag and lift
~1.2%
Field studies of tennis in the heat report sweat losses of about 2.0 ± 0.5 L per hour against intake near 1.5 L per hour, a net deficit of about 1.2% of body mass.
Bergeron et al.
~2%
Performance impairment from dehydration starts at about 2% loss of body mass.
Bergeron et al.
04
A 10-minute extreme-heat break lowered core temperature from 38.92 °C to 38.67 °C in 6 of 7 players.
05
The cause of muscle cramps is contested, but altered neuromuscular control from fatigue is better supported than dehydration and electrolyte loss.
Schwellnus, British Journal of Sports Medicine (2009)

Why it works

The court never changes size. The air does. Wind changes the air the ball flies through, so drag and spin act on a different flow. A tailwind lengthens the flight, a headwind shortens it and steepens the drop, and a crosswind bends it.

Altitude lowers air density. With less air to push through, drag falls, the ball flies further and bounces bigger. That's the Madrid effect, and it changes every rally ball, not only the serve. The sun changes nothing about the ball. It takes the toss out of your eyes for the part of the swing you most need to see.

Heat works on you, not the ball. Most of the energy your muscles use turns to heat, and your core temperature has to stay near 37 °C. In hot conditions, evaporating sweat is the main way out, and humid air slows it down.

The line to say on court
“The court is fixed. The air is the third player. Check it first.”

Drill: The air check

10 min · alone

Before the warm-up, toss a ball straight up at each end and watch it drift. Note where the sun sits on your toss at both ends. Set your margins: higher into the wind, shorter with it.
Weigh yourself before play. Drink to a plan at every changeover, with sodium included.
Weigh yourself after play, add back what you drank, and work out the loss as a share of your body mass.

Number to beatLose no more than 2% of body mass over the session

Faults and fixes

Lobbing into a crosswind

The lob has the longest hang time, so it drifts the most.

FixDrive the pass instead, or lob to the upwind side.

Keeping the same targets in thin air

Every ball flies longer at altitude, not only the serve.

FixAim shorter and use more spin from the first game.

Drinking plain water in the heat

It under-replaces sodium.

FixDrink electrolytes to a plan. Cramps are mostly fatigue anyway.

Flattening the serve into the wind

It flattens exactly the ball the headwind is already dropping.

FixKeep the full swing and add net clearance. The wind holds it in.

Questions players ask

How should I serve into the wind?

Give it more net clearance and keep a full swing. The headwind adds drag, so a serve that would fly long in still air lands in.

Does the ball fly further at altitude?

Yes. Thinner air means less drag, so the ball flies further and bounces bigger. It affects every rally ball, not only the serve, so aim shorter and use more spin.

How much should I drink playing tennis in the heat?

Drink to a plan at every changeover, with sodium, and weigh yourself before and after. Performance starts to suffer at around 2% loss of body mass.

Are tennis cramps caused by dehydration?

Mostly not, though it's contested. The better-supported explanation is altered neuromuscular control from fatigue.

Which shots does the wind affect most?

The ones with the longest hang time: lobs, kick serves and high defensive balls.

What this doesn't cover

There's no reliable number here for how many metres further a ball flies for a given altitude, temperature or wind speed, only the direction of each effect. Whether mild dehydration under 2% hurts an intermittent skill sport like tennis isn't settled.

Sources

Tennis Warehouse University: tennis ball trajectories, drag and lift
Mehta: review of tennis ball aerodynamics
Bergeron et al. (1995, 2014): tennis in the heat
Schwellnus (2009), British Journal of Sports Medicine
Frontiers (2024): cooling strategies

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