ATP Heat Rule 2026: WBGT Thresholds, Cooling Breaks, and Match Tactics

The rule in plain English

The Association of Tennis Professionals has approved an extreme heat policy that goes live in 2026. It is built on the Wet Bulb Globe Temperature, a field measure of heat stress that blends temperature, humidity, sun exposure, wind, and radiant heat. When the WBGT reaches 30.1°C during the first two sets of a best of three singles match, either player can activate a supervised 10 minute cooling break after the second set. If the WBGT exceeds 32.2°C, play is suspended. During the break, players can rehydrate, change clothes, shower, and receive coaching under medical supervision. See the full details in ATP's new heat rule for 2026 and this Reuters summary of the policy.

For additional context on heat planning, see our WBGT rules and training guide.

What those numbers really mean

WBGT is not the number on your weather app. It is closer to a heat budget for your body. In direct sun with humidity and low wind, a WBGT of 30°C can play very differently than a dry 30°C in shade. Crucially, the 30.1 trigger does not end the match. It inserts a recovery window between sets two and three if a player elects it. The 32.2 cutoff is the hard stop that prioritizes health over schedule.

Tennis bodies outside the men’s tour have long used similar triggers, which means players and coaches already have playbooks to adapt. The new men’s rule aligns with that direction of travel and brings consistency to week in, week out tour events.

How the new rule changes match tactics

1) You now pace two sets with a reset in your pocket

If the WBGT hits 30.1 in the first two sets, the third set can begin after a 10 minute cooling window. That reality changes risk management.

• Front load your aggression when receiving. The warmest stretch often sits late in set two. Taking bigger cuts on return games early can secure the scoreboard buffer you want before the break.
• Hold serve with patterns, not pace. On scorchers, a small drop in serve speed that lifts first serve percentage is usually a win. Fewer lung busting second serve rallies protect energy until the cooling window.
• Use the final two games of set two as a pre break setup. If you are serving at 4 5, do not overextend to force a tiebreak. Securing fresh legs post break can be smarter than emptying the tank to rescue that set.

Example: You split breaks and reach 3 3 in set two with the WBGT at 30.4. Simplify serve targets wide and body, shorten points with first ball forehands, and accept a tiebreak or even a 4 6 loss rather than chase every long rally. The break is coming, and your third set can be played with restored clarity.

2) Time management becomes a skill, not a habit

In extreme heat, the 25 second serve clock feels shorter. The best players will build cooling into the rhythm of changeovers and between point pacing.

• Walk the longer route to the towel when you lose a long rally, not when you win it. You bank micro recovery where the risk is highest.
• Learn shade maps for each court. On many stadiums, shade reaches the ad side baseline first in late afternoon. Change the side you bounce on before serves to grab cooler air.
• During the break, follow a checklist: cold fluids, ice towel on neck and forearms, shoes and socks aired, fresh dry shirt and wristbands, headband swap, and a one minute quiet reset with eyes closed and slow nasal breathing. The order matters because the clock is unforgiving.

3) Coaching during the break can flip a match

Because coaching is allowed during the cooling break, treat those 10 minutes like a mini film session.

• Ask for one pattern that is working and one to park. Keep it to two cues.
• Get a single depth cue. Your coach might say, "Aim through the baseline tape for three games" to lift net clearance while you find your legs.
• Lock a first game plan for set three. Serve placement for points one and two, a return position on second serve, and a rally ball height target. For a broader look at sideline input under new rules, review Australian Open coaching changes.

4) The pause can become a trap if you do not train it

Body temperature often rebounds upward 5 to 10 minutes after cooling because blood redistributes and movement resumes. If you sprint into the third set without a re warm plan, you risk feeling heavy or dizzy two games later. Practice a re entry routine: three gentle acceleration runs, six shadow strokes with higher finish, then three first serves at 80 percent before the first point of the third.

Off season preparation: earn your heat armor

Heat tolerance is trainable. In the eight weeks before the Australian summer swing, plan a structured block.

A 10 to 14 day acclimation protocol

• Days 1 to 3: 60 to 70 minutes of easy aerobic work in heat, such as bike or light on court movement, aiming for a steady sweat. End with five minutes of quiet breathing in shade, hands and forearms cooled with ice towels.
• Days 4 to 7: On court 75 to 90 minutes. Rally games to 21 with constraints that lift footwork intensity but cap point length. For example, two ball live feeds into three ball rallies, then a ball pickup walk in shade.
• Days 8 to 14: Match play simulations, two short sets with a 10 minute cooling break between sets. Run the exact break protocol you will use in competition. Practice the re warm routine.

Key markers of progress: your heart rate at a given pace drops, you perceive less effort for the same drills, and you can hold conversation on changeovers. If you lose more than 2 percent of body mass in a session, your hydration plan needs adjusting and the next day should be lower intensity.

Hydration and fueling that actually work on court

• Start well topped up. Two hours pre match, drink roughly 5 to 7 milliliters of fluid per kilogram of body mass, with sodium present. For a 70 kilogram player, that is about 350 to 500 milliliters.
• Know your sweat rate. Weigh before and after a hard 60 minute practice in similar conditions, noting how much you drank. Every kilogram of mass lost equals about one liter of sweat. Aim to limit losses to about 2 percent of body mass.
• Sodium matters. Many players lose 700 to 1200 milligrams of sodium per liter of sweat. Start with 500 to 700 milligrams per hour in sticky conditions and adjust from your cramp history and weigh ins.
• Use portable cooling: ice slurries in an insulated bottle, cooling towels on the neck and forearms, and swapping to dry wristbands every changeover reduce perceived exertion.
• Refuel between sets. A small carbohydrate gel or a few sips of a 6 to 8 percent carbohydrate drink every 15 to 20 minutes keeps decision making sharp.

Parents: pre cool the car and pack two coolers. One is for drinks and gels, one is for towels and spare clothes. Coaches: reserve a shady bag drop spot and a dedicated trash bag for wet towels and shirts so the player’s chair area stays dry.

Off Court training is the most underused lever in tennis. Use the app to build your acclimation calendar, hydration targets, and practice break routines so your athlete hits week one of the season heat ready.

Mental skills for discomfort tolerance and clear decisions

Heat exposes mental habits. It punishes flinch and rewards structure.

• Write a Heat Script. One card in your bag that lists your three cues: Breathing, Tempo, Height.
• Practice a 60 second reset. Sit, one hand on chest and one on belly, close eyes, four breaths in through the nose, six out through the mouth, then open your eyes and list one serve target and one rally pattern out loud. This becomes automatic during the actual cooling break.
• Decision anchor in heat: play to space, not to pace. Tell yourself, "Big targets first three games of the third" so you stay aggressive without trimming margins too fine when your legs are heavy.
• Rehearse distress tolerance. In practice, add a short forfeit, such as three burpees, every time you complain about the heat. You train your language to be task focused.

Coaches can reinforce with simple questions, not lectures: What is your next serve target, what is your recovery action, what is your rally height? The athlete answers, you nod, they own the plan.

Smart gear tweaks for hot courts

Cooling accessories and apparel

• Hats with dark under brim fabric reduce glare; light outer colors reduce radiant heat. Bring two hats and rotate them with a quick rinse in the cooler between sets.
• Cooling towels that hold water while staying light are worth the space. Use them on neck and forearms, not just shoulders, to cool blood flow.
• Sunglasses that fit under a cap brim protect energy by lowering squint and neck tension during service tosses. Practice with them before match day.
• Fabrics with open knit mesh in high sweat zones breathe better than tight knits. Choose shirts with venting along the spine and underarms and shorts with perforations.

Racquet and string setup

• Lower string tension by 1 to 2 kilograms in extreme heat if balls and strings are flying.
• Try a slicker, shaped polyester main with a less stiff cross for spin and pocketing at lower swing speeds. If your arm is sensitive, use a softer co polyester or a multifilament cross to keep shock down on late contact.
• Use sweat friendly overgrips and change them often. A dry handle is accuracy. For summer ball behavior and setups, see our ball standardization guide for Australia.

Ball bounce and movement

Hot courts play faster and higher. Balls get springy and felt fluffs off, especially on hard courts in the Australian summer. Prepare to:

• Return from a half step deeper to buy a fraction of a second and then step forward if the serve sits up.
• Add more height on rally balls to keep the bounce above your opponent’s strike zone while you recover.
• Use the drop shot sparingly right after the cooling break. Opponents may move stiffly as they re warm, but if you miss your first one, you give away a cheap point. Wait until you have dragged them wide twice, then show it.

Practice scenarios that map to the new rule

• Set builder with break: Play two short sets to four games, no ad, with the break triggered if your coach calls out an imaginary WBGT of 30.1. Run the full 10 minute script before the deciding set to four games. Record how you feel in games one and two of the third.
• Heat ladder: Ten point tiebreaks where every third point both players walk to the towel, place hands and forearms on cold towels for fifteen seconds, then resume. You train quick cooling without losing focus.
• Serve plus one in heat: Two baskets, one at 80 percent power, one at 95 percent. Alternate every five serves and track first serve percentage and plus one errors. The goal is to find the leveraged pace that survives heat, not to hit hardest.

What coaches should track in real time

• Carry a simple WBGT reader or a reliable app that estimates it from on site sensors. Many events will announce the number, but it helps to see your own live value.
• Build a heat card for each athlete: sweat rate, sodium target per hour, shoe and sock change timing, preferred ice towel placement, and a one line mental cue.
• Have a red flag checklist for when to pull the plug. If coordination looks off, speech gets slow, or the athlete reports chills or goosebumps, you are past hard tennis and near a health risk.

Making the Australian summer work for you

Travel smart. Arrive early enough to get five or more outdoor sessions in the destination climate. Book late afternoon practice courts to match likely match times. Reserve indoor recovery options such as a cold plunge or a pool, and plan shade strategies at each venue. If you play a lead up event on a slower court, adjust your string tension and ball shape when you transition to a quicker Australian Open series venue.

Parents: plan cold food that tolerates the heat. Grapes, orange slices, rice balls with a pinch of salt, pretzels, and yogurt tubs in a cooler beat chocolate bars and heavy sandwiches. Coaches: scout the venue for misting fans, shade tents, and water stations before your player even arrives.

The broader picture: tennis is getting smarter about heat

The goal is not to make competitions cozy. It is to define clear actions when conditions cross specific risk thresholds. The WBGT numbers give players and coaches something they can plan around, and the mandated break gives them a lever they can actually pull in the heat of a match. That clarity rewards the teams who prepare.

OffCourt exists for that preparation. Use it to script your cooling break, schedule your acclimation block, and set hydration alerts that match your sweat rate.

Final takeaway

Heat will still test nerve and lungs. The difference in 2026 is that the rulebook now gives you structure. Learn the thresholds, practice the break, hardwire your routines, and pack the right gear. If you do, hot spells turn from chaos into a competitive edge.