The same campus reading means different things for a football practice, a band rehearsal, a PE class and a kindergarten recess. Equipment, duration, supervision and the age of the people involved all move the answer.
Get the number from the WBGT calculator or a device at the activity site, then read across for the group going outside.
Athletic practice
Your state association's numbers govern. These are the widely adopted baseline.
| WBGT | Practice | Breaks | Equipment |
|---|---|---|---|
| Under 82.0°F | Normal | 3 per hour, 3 min | Normal |
| 82.0 to 86.9°F | Normal, monitor closely | 3 per hour, 4 min | Normal |
| 87.0 to 89.9°F | 2 hours maximum | 4 per hour, 4 min | Helmets and shoulder pads only |
| 90.0 to 92.0°F | 1 hour, no conditioning | 20 min in the hour | No protective equipment |
| Above 92.0°F | Cancel outdoors | — | — |
Marching band rehearsal
Band has three disadvantages athletics does not: asphalt instead of grass, a uniform that traps heat, and usually no athletic trainer on site.
| WBGT | Rehearsal | Breaks | Uniform |
|---|---|---|---|
| Under 82.0°F | Normal | Every 45 min | Full uniform permitted |
| 82.0 to 86.9°F | Normal, monitor closely | Every 30 min | Hats and jackets off |
| 87.0 to 89.9°F | 1 hour maximum | 10 min every 30 min | No uniform, light clothing only |
| 90.0 to 92.0°F | Move indoors | — | — |
| Above 92.0°F | Cancel outdoors | — | — |
Add roughly 5°F for a full marching uniform with hat and jacket, and remember that an asphalt lot runs considerably hotter than the grass field a weather reading describes.
PE and recess
Simple triggers work better here than a nuanced chart, because the people applying them are teachers and aides rather than athletic trainers.
| WBGT | PE class | Recess |
|---|---|---|
| Under 82.0°F | Normal activity, water available | Normal, water and shade available |
| 82.0 to 86.9°F | Reduce sustained running, break every 20 min | Normal, encourage shade, check surface temperatures |
| 87.0 to 89.9°F | No sustained vigorous activity, shaded breaks | 20 minutes maximum, shaded areas only |
| 90.0 to 92.0°F | Move indoors | 15 minutes maximum in shade, or indoors |
| Above 92.0°F | Indoors | Indoors |
Uniform and equipment adjustments
Add to the reading before looking it up.
| Worn | Add |
|---|---|
| Shorts and a shirt | 0°F |
| Helmet only | about 2°F |
| Helmet and shoulder pads | about 4°F |
| Full football pads | about 6°F |
| Full marching uniform with hat and jacket | about 5°F |
On the day
- Take or compute the reading at the activity site about 15 minutes before it starts.
- Add the adjustment for what the group will be wearing.
- Read across for that group and announce the plan before anyone goes out.
- Make sure water and shade are at the site, and cooling capability is ready from roughly 80°F upward.
- Recheck every 30 minutes and log every reading with the time.
- If any individual is struggling, treat that as the signal, regardless of what the number says.
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.
The campus number, forecast ahead
Band directors, PE staff and administrators can all check the same reading and the hourly forecast, so a rehearsal can be moved to the morning before anyone is standing on the lot.
- 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
What WBGT is too hot for school activities?
It depends on the activity. Athletic practice generally stops above 92°F WBGT; band rehearsal should move indoors around 90°F; PE should move indoors around 90°F; and recess should be limited from the mid 80s and indoors above 90°F.
How much does a marching uniform add to WBGT?
Roughly 5°F for a full uniform with hat and jacket. Band also typically rehearses on asphalt, which runs well above the grass surface a weather-derived reading assumes, so both adjustments apply.
Is there a WBGT threshold for recess?
No national standard exists. A common practical approach limits outdoor time progressively from the mid 80s and moves indoors above roughly 90°F WBGT, with an additional check on playground surface temperatures, which can burn skin before the air is dangerous.
Does PE need a different threshold than athletics?
Usually a more conservative one. PE classes include students of mixed fitness with no acclimatization period and no athletic trainer present, so the triggers should be simpler and earlier than a team practice chart.
Who should check the number at a school?
A named role with authority to modify or cancel activity, usually the athletic trainer. Band directors and PE staff should either receive the reading from that person or have a clear way to check it themselves before taking students out.
Related WBGT guides
Know the real heat number
Real-time WBGT, flag levels and forecasts. Free on iPhone.
