High school heat policy is set state by state, by each state's athletic association, which means there is no single national answer to what your school has to do. There is a clear direction of travel: from heat index to WBGT, and from recommendation to requirement.
Underneath the variation, the components of a good program are the same everywhere, and they are not expensive. What separates schools where nothing happens from schools where someone collapses is whether the components are actually in place when it is inconvenient.
The four components
A reading at the field
WBGT at the practice surface, 15 minutes before activity and every 30 minutes during, logged with the time.
Someone with authority
Usually the athletic trainer, named in the policy, able to modify or stop practice without negotiating with a coach.
A heat acclimatization period
Graded practice length, equipment and double-session limits across the first five days of preseason.
Cold-water immersion, filled
A tub, water and ice, on the field before practice from roughly 80°F WBGT. This is what makes exertional heat stroke survivable.
How state rules differ
Associations differ on four axes, and it is worth knowing where yours sits on each.
Measure: some require WBGT, some still permit heat index, some leave it to districts. Force: some rules are mandatory with enforcement, others are recommendations. Scope: most cover athletics only; a few now include marching band. Thresholds: some publish one state-wide set, others vary by region, recognising that an acclimatized population in a consistently hot area is a different case from a cooler one.
Texas is currently the most developed example. The UIL WBGT policy, mandatory from August 1, 2026, requires WBGT rather than heat index, covers marching band as well as athletics, sets thresholds by region, and specifies reading intervals, logging and a cold-water cooling zone.
Check your own association's current policy directly rather than relying on what was true a few seasons ago. Several have changed recently.
The heat acclimatization period
Most exertional heat illness in school athletics happens in the first three to five days of preseason. This schedule is the single highest-value intervention a program makes.
- Days 1 to 2: one practice per day, three hours maximum, helmets only for football, no contact.
- Days 3 to 5: one practice per day, three hours maximum, helmets and shoulder pads, contact limited to sleds and dummies.
- Days 6 onward: full equipment permitted and double practice days may begin.
- Double days are separated by at least three continuous hours of rest and never run on consecutive days.
- Walk-throughs do not count as practice if they involve no conditioning or equipment and are separated from practice by three hours.
- Anyone who starts late, including transfers, begins their own count at day one rather than joining the team's.
What parents should ask
A program doing this properly will answer immediately. Hesitation is the answer.
- Do you measure WBGT at the practice field, and how often is it recorded?
- Who takes the reading, and who can stop practice?
- Is a cold-water immersion tub filled and on the field during August practices?
- Is a certified athletic trainer present at practices, not only at games?
- What is the acclimatization schedule for the first five days?
- Does the heat policy cover marching band and other outdoor activities?
- Is water available at all times, or only at scheduled breaks?
Warning signs of heat illness
Heat stress shows up before it becomes an emergency. Anyone on site should speak up immediately on any of these:
When in doubt, cool first and call for help. Collapse or confusion in the heat should be treated as possible exertional heat stroke: begin cold-water immersion immediately and call 911. Cooling comes before transport.
Check it yourself
Parents, coaches and directors can all see the same real-time WBGT for the school's town, with an hourly forecast, so the conversation about this afternoon's practice starts from a number rather than an impression.
- Real-time WBGT for your location or any city
- Hourly and 14-day WBGT forecasts to plan ahead
- Color-coded flag levels with mode-specific guidance
- Humidity, wind, sun and cloud cover behind every reading
WBGT is estimated from weather data with the peer-reviewed Liljegren model. Where a policy requires on-site measurement, use the app for planning and as a cross-check alongside your instrument.
Common questions
Do all states require WBGT for high school sports?
No, but the number is growing. Some states require it, some permit heat index as an alternative, and some leave it to districts. Texas made WBGT mandatory for outdoor practice and marching band from August 1, 2026 through the UIL.
Who takes the WBGT reading at a high school?
Your policy should name a role, usually the athletic trainer, with authority to modify or cancel activity. The reading is taken at the practice site about 15 minutes before activity and every 30 minutes during, and logged each time.
What is the heat acclimatization period?
A graded schedule across the first five days of preseason that limits practice length, equipment and double sessions while athletes adapt to the heat. It exists because most exertional heat illness happens in that window.
Should marching band be covered by the athletic heat policy?
Yes. Band rehearses on asphalt in uniform for long stretches, typically without an athletic trainer present, which is comparable to or worse than athletic exposure. Texas now includes it explicitly, and other states are following.
What should a school have on the field in August?
A WBGT reading taken at the field, unrestricted water, shade, a cold-water immersion tub filled before practice, a written emergency action plan that staff have rehearsed, and ideally a certified athletic trainer present at practices.
Related WBGT guides
Know the real heat number
Real-time WBGT, flag levels and forecasts. Free on iPhone.
