On this page · 8 sections
What does the NMAA require?
Under Bylaw 7.6.21, each school is responsible for obtaining either a Wet Bulb Globe Temperature or a heat index reading at the site of practices and competitions. The NMAA says WBGT considers more environmental factors than heat index and should be a school’s first choice when evaluating conditions and planning activities.
Without a WBGT reading, a digital psychrometer or other instrument may be used at the site to measure the heat index, and a weather app on a phone is permissible only if no other instrument is available. A cold-water immersion tub or other rapid on-site cooling should be available for all warm-weather practices, and athletes should always have access to water.
WBGT first
WBGT is the NMAA’s first choice. Heat index is the fallback, measured at the site of the activity.
Rest by the minute
Bands set minutes of rest per hour: at least 10, then at least 15, then 20 — spread across the hour.
Rapid cooling
A cold-water immersion tub or other rapid on-site cooling for warm-weather practices. Immerse before transporting.
Games too
Above WBGT 87 or heat index 95, soccer and football games get a heat time-out. Above 92.0 WBGT, no outdoor competition.
The NMAA practice threshold table
Four practice bands. Each is printed twice: as a WBGT reading and as a heat index, so read the column for the measurement you took. The row colour follows the Flash alert scale your athletic trainers already see in the app.
| WBGT | Heat index (°F) | Activity limit | Rest breaks | Football equipment |
|---|---|---|---|---|
| < 87 | < 95 | No time limit listed | At least 10 minutes of rest breaks distributed throughout each hour; two to three separate breaks recommended | None listed |
| 87 – 89.9 | 95 – 99 | Maximum practice time is 2 hours | At least 15 minutes of rest breaks distributed throughout each hour; three to four separate breaks recommended | Helmets, shoulder pads and shorts during practice that does not involve contact; all protective equipment removed during conditioning |
| 90 – 92 | 100 – 104 | Maximum practice time is 1 hour; no conditioning activities | 20 minutes of rest breaks distributed throughout the hour | No protective equipment during practice that does not involve contact |
| Above 92.0 | Above 104 | No outdoor practice until WBGT is 92.0 or below or heat index is 104 or below | — | — |
Source: NMAA Bylaw 7.6.21, Heat Illness Prevention Protocol, Practice Protocols (nmact.org protocol sheet and Handbook Section VII), checked 15 Oct 2026. Ranges as printed. If the heat index or WBGT rises into the second band during practice, football players may continue to work out in football pants without changing to shorts. Competitions follow separate protocols: heat time-outs above WBGT 87 or heat index 95, no outdoor competition above 92.0 WBGT or heat index 104.
Where does Flash fit?
Flash is a forecast for planning, not an on-site meter: the NMAA bands apply to the reading taken at the site. 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 NMAA 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 NMAA's
6:30 pm · The reading that decides the day
The band you land in sets the clock, the rest minutes and the pads.
Flash 6-hour WBGT outlook for the practice field: 86 by 3 pm, into 87–89.9 by 4 pm. The athletic director flags the football session.
Decision: run at 4 pm under the 2-hour cap with at least 15 minutes of rest each hour, or push to 6:30 pm. The AD pushes. The bus, the trainers and the parents hear now, not at 3:45.
WBGT reading at the field: 85.0, under 87. At least 10 minutes of rest each hour, split across two or three breaks, and the cooling 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?
Bylaw 7.6.21 makes each school responsible for taking the reading at the site. Keeping the readings and decisions together means a question from the NMAA, the district or a parent is answered from one folder.
- The reading for each practice and competition, with the time, whether it was WBGT or heat index, and the instrument used.
- The band each reading fell in and the decision it triggered: practice length, rest minutes, football equipment.
- For games above WBGT 87 or heat index 95: the heat time-outs taken.
- The rapid on-site cooling plan, with the cold-water immersion tub or equivalent.
- 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)
- 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 Carolina (SCHSL)
- South Dakota (SDHSAA)
- Utah (UHSAA)
- Vermont (VPA)
- Virginia (VHSL)
- Washington (WIAA)
- Wisconsin (WIAA)
Sources
- NMAA — Heat Illness Prevention Protocol, NMAA Bylaw 7.6.21. Practice and competition protocols, measurement, cooling. Checked 15 Oct 2026.nmact.org/file/Heat_Illness_Prevention_Protocol.pdf (opens in a new tab)
- NMAA — Handbook Section VII, Sports Regulations, 7.6.21 Heat Illness Prevention Protocol. Checked 15 Oct 2026.nmact.org/file/Section_7_General.pdf (opens in a new tab)
NMAA documents are published at nmact.org (opens in a new tab).
Frequently asked
No. The NMAA bands apply to the WBGT or heat index reading taken at the site of the practice or competition. Flash's 6-hour outlook tells you where that reading is heading — a scheduling tool, not a compliance instrument.
Yes, but WBGT should be the first choice. Without a WBGT reading, a digital psychrometer or other instrument at the site may measure the heat index; a phone weather app is permissible only if no other instrument is available.
Games follow separate protocols. Above WBGT 87 or heat index 95, soccer referees stop for a heat time-out of at least five minutes in each half, and football officials stop at the first dead ball after the halfway point of each quarter. Above 92.0 WBGT or heat index 104, no outdoor competition.