On this page · 8 sections
What does the SCHSL require?
All SCHSL schools are required to use a scientifically approved on-site Wet Bulb Globe Thermometer, a cold immersion tub or other effective cooling device, and a venue-specific emergency action plan as primary prevention strategies for exertional heat illness. Schools must also follow the SCHSL pre-season acclimatization plan.
Readings are taken directly on the playing surface 30 minutes before activity and every 30 minutes after. Local weather updates and phone apps are not accepted for the venue reading. Once a reading has stayed in a range for 15 minutes, that range’s restrictions are in place and cannot be lowered; if the reading climbs and stays in a higher range for 15 minutes, the new range applies. At 92.1 or above, practices and competitions are suspended or postponed.
Reading cadence
On the playing surface, 30 minutes before activity, then every 30 minutes. Phone apps are not scientifically approved.
Range lock-in
15 minutes in a range puts its restrictions in place. Higher ranges apply once held for 15 minutes; no dropping to a lower range.
The device
A scientifically approved WBGT thermometer, recalibrated every two years or sooner if the manufacturer recommends it.
Cold-water immersion
At a WBGT of 82 or greater, outdoor sports have immediate access to a cold immersion tub or another water method, such as a tarp.
The SCHSL WBGT threshold table
Five bands, read in degrees Fahrenheit from the on-site WBGT device. The SCHSL prints activity and rest-break guidelines together; they are split into columns here, word for word. The row colour follows the Flash alert scale your athletic trainers already see in the app.
| WBGT (°F) | Activity limit | Rest breaks | Equipment |
|---|---|---|---|
| Under 82.0 | Normal activities | At least three separate rest breaks each hour of minimum duration of 3 minutes each during the workout | None listed |
| 82.0 – 86.9 | Use discretion for intense or prolonged exercise; watch at-risk players carefully | At least three separate rest breaks each hour of a minimum of 4 minutes duration each | None listed |
| 87.0 – 89.9 | Maximum practice time is two hours | For all sports: at least four separate rest breaks each hour of a minimum of 4 minutes each | For Football: players restricted to helmets, shoulder pads, and shorts during practice. All protective equipment must be removed for conditioning activities |
| 90.0 – 92.0 | Maximum length of practice is one hour; there may be no conditioning activities. Competitions involving high intensity effort, in which breaks are not possible (e.g. Cross Country meets), should be delayed until WBGT reading is below 90 or canceled | 20 minutes of rest breaks provided during the hour of practice | No protective equipment may be worn during practice |
| Over 92.1 | No outdoor workouts; Cancel exercise; delay practices until a cooler WBGT reading occurs | — | — |
Source: SCHSL Heat and Acclimatization Guidelines (updated April 2024), section 3, on schsl.org, verified 15 Oct 2026. Ranges as printed. Section 2(d) of the same document says that at 92.1 or above, practice and competitions are suspended or postponed. Rest time involves unrestricted access to fluids, in a shaded area, with helmets removed in sports that use them.
Where does Flash fit?
Flash is a forecast for planning, not an on-site meter: SCHSL compliance uses the reading from your scientifically approved WBGT on the playing surface, and the guidelines rule out weather apps for that reading. Flash's 6-hour WBGT outlook tells you at 1 pm what the 4 pm reading is likely to be, so you can move practice instead of cancelling it.
Heat: plan, don't cancel
The outlook runs per field for every hour of the afternoon, against the five SCHSL bands. Shift the start, swap the equipment plan or go indoors before the cars arrive.
Lightning: up to 60 minutes ahead
Strike-level prediction on a 1×1 km cell, refreshed every 2 minutes. Up to 99.6% lightning prediction accuracy on a one-hour window, measured against NLDN ground-truth strikes — method published.
Accuracy methodReturn to play: the all-clear timer
After the last strike inside your radius, Flash runs your policy's all-clear timer and logs it, so play resumes on evidence.
Weather Command Center
Flash Heat and WBGT prediction 6-hour WBGT outlook, heat index, air temperature and dew point per 1×1 km cell
What does a planning day look like?
Illustrative example · Not live weather — the readings are examples, the rules are the SCHSL's
6:00 pm · The reading that decides the day
The band you land in sets the clock, the breaks, the pads and the cold tub.
Flash 6-hour WBGT outlook for the practice field: 86 by 3 pm, into 87.0–89.9 by 4 pm. The athletic director flags the football session.
Decision: run at 4 pm under the two-hour cap in helmets, shoulder pads and shorts with four 4-minute breaks an hour, or push to 6:30 pm. The AD pushes. The bus, the trainers and the parents hear now, not at 3:45.
First reading on the playing surface, 30 minutes before practice: 84.1, the 82.0–86.9 band. Three 4-minute breaks per hour go on the plan and the cold immersion tub is ready.
Flash lightning alert: a strike is predicted inside the site radius within the next 60 minutes. The field clears.
Last strike inside the radius. Flash starts the all-clear timer.
All clear. Practice resumes; the alert log records who was warned, when, and when play returned.
What should the athletic director keep on file?
The SCHSL guidelines make the on-site WBGT, the cooling tub and the emergency action plan requirements for every school. Keeping these together means a question from the SCHSL, the district or a parent is answered from one folder.
- WBGT readings with times, taken on the playing surface 30 minutes before activity and every 30 minutes after.
- The band each reading fell in and the decision it triggered: practice length, rest breaks, football equipment.
- The WBGT device used and its calibration date (every two years, or sooner if the manufacturer recommends).
- The venue-specific emergency action plan, with the cold immersion tub or other cooling method on hand from a WBGT of 82.
- The Flash alert log: lightning alerts, who was notified, the all-clear, and the 6-hour outlook the schedule decision was based on.
Which other states publish WBGT policies?
Every state page follows this template: verified thresholds, the reading cadence, what to keep on file, and where the WBGT forecast fits.
State by state
Same instrument, different bands — the WBGT forecast travels with you.
- Georgia (GHSA)
- Texas (UIL)
- Florida (FHSAA)
- Arizona (AIA)
- Arkansas (AAA)
- Colorado (CHSAA)
- Hawaii (HHSAA)
- Illinois (IHSA)
- Kansas (KSHSAA)
- Massachusetts (MIAA)
- Mississippi (MHSAA)
- Missouri (MSHSAA)
- Nevada (NIAA)
- New Hampshire (NHIAA)
- New Mexico (NMAA)
- North Carolina (NCHSAA)
- Ohio (OHSAA)
- West Virginia (WVSSAC)
- Oklahoma (OSSAA)
- Alabama (AHSAA)
- California (CIF)
- Connecticut (CIAC)
- Iowa (IHSAA / IGHSAU)
- Kentucky (KHSAA)
- Louisiana (LHSAA)
- Minnesota (MSHSL)
- Nebraska (NSAA)
- New Jersey (NJSIAA)
- New York (NYSPHSAA)
- South Dakota (SDHSAA)
- Utah (UHSAA)
- Vermont (VPA)
- Virginia (VHSL)
- Washington (WIAA)
- Wisconsin (WIAA)
Sources
- SCHSL — Heat and Acclimatization Guidelines (updated April 2024). Thresholds, reading cadence, range lock-in, competition rules, cooling. Verified 15 Oct 2026.schsl.org/wp-content/uploads/2024/07/Heat-Guidelines-Updated_-April-2024-3.pdf (opens in a new tab)
- SCHSL — Health & Safety Library, Heat and Acclimatization Guidelines page. Verified 15 Oct 2026.schsl.org/archives/11549 (opens in a new tab)
- SCHSL — 2026 Football Pre-Season Practice Guidelines. Verified 15 Oct 2026.schsl.org/wp-content/uploads/2026/06/PreseasonPractice-FB-2026.pdf (opens in a new tab)
SCHSL documents are published at schsl.org (opens in a new tab).
Frequently asked
No. The SCHSL requires a scientifically approved on-site WBGT and says not to rely on weather updates or apps for the venue reading. Flash's 6-hour outlook tells you where that reading is heading — a scheduling tool, not a compliance instrument.
On the playing surface 30 minutes before activity, then every 30 minutes. Once a reading has held in a range for 15 minutes, that range’s restrictions stay in place for the session.
During warmups, players remove helmets and shoulder pads when the WBGT is above 87. If the WBGT is above 87.0 and below 92.1 at kick-off, there is a mandatory three-minute hydration break at the halfway point of each quarter, with helmets off and unlimited water.
All sports that participate outdoors should have immediate access to a cold immersion tub, or another method that uses water, when the WBGT is 82 or greater. The SCHSL notes this is typically needed from May through October.