On this page · 8 sections
What does the NSAA recommend?
The NSAA Board of Directors approved the WBGT as the recommended measurement practice and device for heat and humidity at practices and contests. Its use is recommended throughout the calendar year when the ambient temperature is above 80 degrees, and the WBGT should be measured every 30 minutes.
The guidelines print each band for Region 1 and Region 2, and the NSAA lists which region each school falls in by zip code. Participants should always have unrestricted access to water, at-risk athletes should be monitored closely, and schools should have an exertional heat illness emergency action plan.
Reading cadence
Every 30 minutes, year-round, whenever the ambient temperature is above 80 degrees.
Region 1 or Region 2
The NSAA assigns each school a region by zip code. Region 1 bands start lower.
Cold-water immersion
Available from the second band up: 76.2 in Region 1, 79.8 in Region 2.
Contests
From the third band, per NFHS rules, additional or extended timeouts for rest and water breaks.
The NSAA WBGT threshold table
Five bands, read in degrees Fahrenheit from the WBGT device, printed for two regions. The row colour follows the Flash alert scale your athletic trainers already see in the app.
| Region 1 | Region 2 | Activity limit | Rest / water breaks | Equipment |
|---|---|---|---|---|
| Under 76.1 | Under 79.7 | Normal activities | 3 separate - 3 to 5 minute rest / water breaks per hour | None listed |
| 76.2 – 81 | 79.8 – 84.6 | Use discretion for intense / prolonged practice. Monitor at-risk athletes closely. Cold water immersion available | 3 separate - 4 to 6 minute rest / water breaks per hour | None listed |
| 81.1 – 84 | 84.7 – 87.6 | Maximum practice time is 2 hours. Monitor at-risk athletes closely. Cold water immersion available. Contests: per NFHS rules, implement additional/extended timeouts for rest / water breaks | 4 separate - 4 to 6 minute rest / water breaks per hour | Helmets and shoulder pads only. Remove helmets and shoulder pads if conditioning |
| 84.1 – 86.1 | 87.7 – 89.7 | Maximum practice time is 1 hour. No conditioning. Monitor at-risk athletes closely. Cold water immersion available. Contests: per NFHS rules, implement additional/extended timeouts for rest / water breaks. Contests: consider delaying / postponing start times | 4 separate - 5 to 7 minute rest / water breaks per hour | Helmets and shoulder pads prohibited |
| Over 86.1 | Over 89.7 | No outdoor activities. Cancel or delay outdoor practices / contests until lower WBGT is recorded | — | — |
Source: NSAA Wet Bulb Globe Thermometer (WBGT) Heat Modification Guidelines (nsaahome.org), checked 15 Oct 2026. Ranges as printed; the NSAA prints the guidelines in capitals.
Where does Flash fit?
Flash is a forecast for planning, not an on-site meter: NSAA guidance runs on the WBGT measured every 30 minutes. 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 bands for your region. 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 NSAA's (Region 2)
6:30 pm · The reading that decides the day
The band you land in sets the clock, the breaks and the pads.
Flash 6-hour WBGT outlook for a Region 2 practice field: 83 by 3 pm, into 84.7–87.6 by 4 pm. The athletic director flags the football session.
Decision: run at 4 pm under the 2-hour cap in helmets and shoulder pads only, or push to 6:30 pm. The AD pushes. The bus, the trainers and the parents hear now, not at 3:45.
WBGT at the start of practice: 82.4, the 79.8–84.6 band. Three 4–6 minute water breaks per hour go on the plan and cold-water immersion is ready. Next reading at 7:00.
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 NSAA guidelines do not set a records rule. Keeping these together still means a question from the NSAA, the district or a parent is answered from one folder.
- The school's NSAA region, Region 1 or Region 2, from the NSAA zip-code list.
- WBGT readings with times, every 30 minutes whenever it is above 80 degrees.
- The band each reading fell in and the decision it triggered: practice length, water breaks, helmets and pads, contest timeouts.
- The exertional heat illness emergency action plan, with cold-water immersion.
- 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)
- New Jersey (NJSIAA)
- New York (NYSPHSAA)
- South Carolina (SCHSL)
- South Dakota (SDHSAA)
- Utah (UHSAA)
- Vermont (VPA)
- Virginia (VHSL)
- Washington (WIAA)
- Wisconsin (WIAA)
Sources
- NSAA — Wet Bulb Globe Thermometer (WBGT) Heat Modification Guidelines. Region 1 and Region 2 bands, reading cadence. Checked 15 Oct 2026.nsaa-static.s3.amazonaws.com/textfile/spmeds/wbgtchart.pdf (opens in a new tab)
- NSAA — WBGT school zip-code categories (Region 1 and Region 2). Checked 15 Oct 2026.nsaa-static.s3.amazonaws.com/textfile/spmeds/wbgtschool.pdf (opens in a new tab)
NSAA documents are published at nsaahome.org (opens in a new tab).
Frequently asked
No. NSAA guidance runs on the WBGT measured at the site every 30 minutes. Flash's 6-hour outlook tells you where that reading is heading — a scheduling tool, not a compliance instrument.
The NSAA publishes a list of schools by zip code, each assigned to Region 1 or Region 2. Region 1 bands start lower: outdoor activity stops over 86.1 rather than 89.7.
Yes. From the third band, per NFHS rules, contests add timeouts for rest and water; in the fourth, consider delaying or postponing start times; above the top threshold, contests are cancelled or delayed.