ATP 2026 Heat Rule: Wet Bulb Globe Temperature, Cooling Breaks, and How to Prepare

The policy that will change matches in 2026

Beginning with the 2026 season, the ATP will standardize how tournaments handle extreme heat using wet bulb globe temperature (WBGT), a metric that blends temperature, humidity, sun, and wind into a single stress score. When WBGT readings hit a set threshold, players in best-of-three matches will be eligible for a supervised 10-minute cooling break after the second set, and play can be suspended once the reading crosses a higher stop point. These details matter because they convert weather into rules, not suggestions. If you coach a junior, or you are a player who grinds through summer hard courts, this shift is a competitive lever, not a footnote. The core outlines of the new approach have been reported by Reuters, including the use of WBGT and specific intervention thresholds, bringing the ATP closer to Grand Slam practice on heat management. See the report in Reuters details the 2026 ATP heat policy.

What this means in plain language: the rule will formalize time to cool, rehydrate, change gear, and reset tactics. Matches will no longer depend only on an on-site supervisor’s judgment when the sun is punishing. You should treat these breaks like planned pit stops rather than surprise detours.

Why wet bulb globe temperature, not just air temperature

You cannot prepare for heat by looking at temperature alone. WBGT captures how your body fights the environment. In tennis, where rallies happen in direct sun, on reflective courts, and with limited shade, WBGT tells the truth that a phone weather app tends to hide.

For coaches and parents, this matters for planning. A breezy 92 degrees Fahrenheit with low humidity is not the same as 86 degrees in sticky humidity under direct sun. The second case can be more dangerous. Occupational safety guidance explains why WBGT is a better hazard gauge than simple heat index and offers practical thresholds for work to rest ratios. For a concise overview, see OSHA clarifies why WBGT beats heat index.

Start now: build a heat periodization plan

A new rule does not magically make your body resilient. Heat tolerance is trainable, and the time to train it is long before a tournament week. Use a three-layer plan.

1. Microcycle for acclimation, 10 to 14 days

• Goal: raise plasma volume, improve sweat rate, and train your brain to stay composed when hot.
• How: perform 5 to 7 sessions in the heat across two weeks. Start with 30 to 40 minutes of low to moderate intensity work in a hot environment, then build to 45 to 60 minutes. Keep court time purposeful, such as serve plus one drills, crosscourt patterns, and approach plus volley sequences. Add light conditioning directly after a shorter court block to stack heat exposure without sloppy footwork.
• Safety gates: keep a log of resting heart rate on waking, pre and post body mass, and perceived exertion. If you lose more than 2 percent of body mass in a session or feel dizzy or confused, you went too hard.

2. Mesocycle for performance, 4 to 6 weeks

• Two heat exposures per week at match pace. Example: baseline patterns to targets, serve plus one, then 6 to 8 short practice games to 7 points with 60 seconds on, 60 seconds off. Build specific footwork under fatigue: four-ball patterns ending at the net, then a recovery jog to the baseline while practicing slow nasal breathing. For added court-speed work that pairs well with heat, follow our off-court speed training plan.
• Complement with one off-court cardio session in the heat each week. Stationary bike or treadmill with a hoodie in a warm room can work if outdoor conditions are not safe. Keep intensity submaximal. The goal is heat strain, not maximal lactic work.

3. Maintenance during tournament blocks

• Short daily exposures maintain adaptations. Fifteen minutes of warm-up in the sun, then a shaded dynamic series, is often enough. Avoid adding big new heat loads between matches; the match itself is the training.

Hydration and fueling that actually work on hot days

Hydration is a system, not a sip of water at changeover. Build it into your day.

• Two hours before play: drink 5 to 7 milliliters per kilogram of body mass. A 70 kilogram player would take roughly 350 to 500 milliliters. If your urine is still dark 60 minutes before start, add another small drink.
• Sodium matters. Aim for 500 to 1000 milligrams of sodium per liter of fluid in hot conditions. Heavy sweaters or players with salty sweat marks may need the top of that range. You can get there with a sports drink, an electrolyte mix, or a pinch of table salt plus a flavored drink. The target is sodium per liter, not a random tablet count.
• On-court: most players can absorb 0.4 to 0.8 liters per hour during play without gut distress. Practice your drink pattern in training. Small, regular sips beat big gulps.
• Avoid overhydration. If you are drinking a lot of plain water and not taking in sodium, you can feel bloated, foggy, and weak. That is not mental toughness, that is a dilution problem.
• Weigh in and out. If you are down more than 2 percent post-match, add both fluid and sodium faster. If you finish heavier than you started, you overshot fluids relative to sweat loss.
• Fuel the brain. Glycogen supports decision making late in hot matches. Take in 30 to 60 grams of carbohydrate per hour if your gut tolerates it. Practice this in training with chews, gels, or a drink.

Rehearse the break: your 10-minute cooling blueprint

A cooling break is a skill. Do not waste it figuring things out on the day.

• Second 0 to 60 seconds: sit, slow your exhale, and get two large towel ice wraps on neck and forearms. Feet up if possible. Switch to a dry shirt.
• Minute 1 to 3: sip a cool drink with sodium, about 150 to 250 milliliters, and nibble a small carbohydrate source you have already practiced. Do not chug a full bottle.
• Minute 3 to 6: put on a pre-chilled cooling vest if you use one. Fan yourself or have a teammate do it. Keep exhale longer than inhale to reduce sympathetic drive.
• Minute 6 to 8: tactical reset. Review the three most effective patterns from the first two sets, one serve pattern, one return target, and one baseline pattern. Drop anything that costs too much energy for too little reward.
• Minute 8 to 9: gear check. New wristbands, fresh overgrip, fresh rosin or tack, dry hat. If the balls feel extra lively, lower string tension by 1 to 2 kilograms for your backup frame before the match so you can switch quickly if needed.
• Minute 9 to 10: stand, short shadow swings, two deep belly breaths, first-serve routine in your head.

Practice this sequence in a weekly session. Time it. Drill it until it feels automatic.

Tactics that win in heat

Heat changes the tradeoffs on every point. You are not just playing the score. You are playing your opponent’s cooling rate and your own.

• Serve with purpose, not just power. Hot air is less dense, so flat serves can fly. Do not chase extra miles per hour if it costs first-serve percentage. Use more body serves and wide slice from the deuce side to pull the returner off the court. Aim for 3 to 5 percent higher first-serve percentage than your norm. For a model of brave second serves, study this second-serve blueprint under pressure.
• Shorten the serve plus one. Pre-choose a simple plus-one pattern per side and run it until the opponent proves they can stop it. Example: deuce court wide slice, forehand to open court, then recover and look for a backhand crosscourt cage.
• Adjust rally length by score. Try to shorten points on return at 30 all or break points. A deep, heavy crosscourt return buys time and forces a reactive ball. Follow it with an early court position to invite a shorter rally.
• Use height and shape. Heavier topspin clears the net with margin and bounces high, asking your opponent to work harder for each swing. Mix in short angles and the occasional drop shot to make a heavy-legged opponent stop and start.
• Return position is a heat tool. Move back half a step on very hot days to buy reaction time and reduce frantic footwork, or move in on second serves to end points faster. Test both in the warm-up and early games.
• Come forward more. One extra approach per game can chop 15 to 25 total swings across two sets. That matters in heat.

Gear that buys you degrees

Think of gear in layers: remove heat, manage sweat, maintain grip, control ball speed.

• Cooling: a pre-chilled vest in an insulated bag is legal during breaks where rules allow it. Cold towels on the neck and forearms help. A small battery fan clipped to the fence is a cheap win in practice settings.
• Apparel: light colors, mesh panels, and looser fits improve airflow. Major brands like Nike, Adidas, Asics, and New Balance all offer heat-focused fabrics. Bring at least two shirts, two hats, and three pairs of wristbands for a hot match.
• Head and eyes: a white hat with a dark underbill cuts glare. Polarized lenses help if you use sport glasses, but fog control is the priority. Use anti-fog spray and keep a microfiber cloth courtside.
• Grip: change overgrips often. Bring rosin or a liquid tack if you sweat through grips. Keep a small terry towel by your bag just for hands and forearms.
• Frames and strings: a slightly lighter swingweight can reduce energy cost over time. Do not slash weight without a plan, since too light can stress the arm. If the ball is flying in the heat, go up a string gauge or drop a pound or two on a poly and add a touch of spin rather than muscling the ball flatter. Hybrids or softer multis can reduce shock when the arm gets tired. For deeper context on how hotter conditions change ball speed and string choices, see our ball standardization and string guide.
• Footwear and socks: breathable uppers and thin, wicking socks reduce blister risk. Pack blister patches and a small roll of tape.

Data you can actually use

• Get a simple handheld WBGT meter if your budget allows. If not, track a consistent proxy such as local WBGT readings posted by your tournament, or use a reputable weather app that estimates WBGT. Consistency matters more than perfection.
• Keep a heat log that records WBGT at the start of practice, what you drank, your pre and post mass, and how you felt in the final 30 minutes. You will find your personal tipping points.
• Track heart rate and time to settle between points. If your heart rate takes longer than usual to drop 30 beats in one minute during a changeover, your cooling routine needs work.

Off-court training is the most underused lever in tennis. OffCourt unlocks it with personalized physical and mental programs built from how you actually play. Use OffCourt.app to turn your heat log into a tailored conditioning and hydration plan.

Coaches: a two-part protocol for extreme days

Before the match

• Decide your cooling kit: two large cooling towels, one vest, three spare shirts, spare hat, extra wristbands, rosin, electrolyte bottles labeled by set.
• Rehearse the 10-minute plan in practice earlier that week.
• Pre-match talk: one serve target, one return target, one baseline pattern. Add one fatigue cue such as slower exhale between points.

During the match

• Track changeovers. If your player is getting chatty or unfocused, they are often too hot or underfueled. Guide them back to the simple pattern and the breath.
• If WBGT climbs near the break threshold, remind them what will happen and who will handle the gear and ice. Clarity calms athletes.

Parents and travel managers: make heat an equipment list

• Pack like a small pit crew: soft cooler, several ice packs, two cooling towels, electrolyte packets, extra shirts and socks, hat, sunscreen, blister patches, and a clip fan for practice days.
• Pre-cool the athlete, not the venue. A cool car, cool fluids, and a cool vest are better than a lukewarm bottle at the court.
• Build a post-match plan for hot days: a recovery drink with sodium, a light salty snack, a cool shower, and a short nap. Schedule team dinners later on scorching days.

A one-week heat taper before a hot event

Seven days out

• Two match-intensity practices in the heat, each 60 to 75 minutes with short games. One off-court heat exposure of 30 to 40 minutes on bike or jog.

Four to five days out

• Lower total volume by 20 to 30 percent, but keep intensity. Include one practice at the event’s expected time of day.

Two to three days out

• Short, sharp sets and serve plus one drills in the heat. Emphasize cooling practice and hydration timing.

Day before

• Light hit in similar conditions. Finalize your cooling kit. Early dinner with salt and carbohydrates. Aim for 8 to 9 hours of sleep.

Mental skills that lower heat strain

• Cue words: pick a single word to trigger your cooling routine, such as cool or long. Use it at every changeover.
• Box breathing: four seconds in, six seconds out for one minute at changeovers.
• Narrow the plan: when hot, the brain wants to wander. Reduce your plan to one serve target and one rally pattern for the next two games. Simplicity saves glucose and willpower.

What success looks like in 2026

On a day when WBGT climbs, the rule will grant you time and clarity. The winners will be the players who trained to use both. They will enter the break with a script, reset their physiology, and emerge with a simpler, smarter game plan. They will adjust strings and targets in advance. They will let the environment force their opponent into harder choices.

The sport is moving toward more formal safeguards in heat. Your program should move faster. Build the acclimation block. Rehearse the break. Test the gear. Track what works. Then make those adjustments automatic long before the umpire announces a cooling pause. If you want to see how rule and tech changes reshape tactics at majors, check our look at coaching and AI match tactics.

OffCourt can help you design that system. Off-court training is the most underused lever in tennis. OffCourt unlocks it with personalized physical and mental programs built from how you actually play. Start a heat periodization plan, load your match and practice data, and turn the 2026 policy into a competitive advantage.

The next step

Create a one-page heat playbook this week. List your pre-match drink and sodium targets, your 10-minute break choreography, your three heat-day patterns, your gear list, and your post-match recovery routine. Put it in your bag. Share it with your coach and parents. The weather will not wait for you to adapt, but your training can make the weather work for you.