On this page · 8 sections
What does the NIAA require?
The NIAA guidelines apply to all sports and to every staff member associated with activities where heat illness poses a risk, indoors and outdoors. Environmental monitoring with a WBGT device is the recommended and preferred method, and all schools should have one. Monitoring happens any time it is warm outside, every 30 minutes beginning at the scheduled practice time. If the WBGT device is unavailable or not working, the heat index may be used as a temporary back-up.
Each school designates a trained person — an athletic trainer, athletic director or coach — to monitor the WBGT before practices and contests, and that person is responsible for modifying or cancelling the activity. Each school also designates a monitoring site, and all readings are recorded and stored. Schools follow the activity guidelines for the region category they are located in, from the regional heat-safety map the NIAA reproduces.
Reading cadence
Every 30 minutes, beginning at the scheduled practice time, any time it is warm outside.
Designated person
A trained athletic trainer, athletic director or coach reads the WBGT and decides modification or cancellation.
Set water breaks
Yellow: a 5-minute water break every 30 minutes. Orange: 8 minutes every 30. Red: 20 on, 20 off, 20 on. Helmets off.
Cold-water tub
Set up whenever the WBGT is above the green zone, as close to the practice or contest as possible.
The NIAA WBGT threshold table
Five flag zones, read in degrees Fahrenheit from the WBGT device. Find your region category on the NIAA map, then read across. The row colour follows the Flash alert scale your athletic trainers already see in the app.
| Cat 3 | Cat 2 | Activity limit | Rest and water breaks | Football equipment |
|---|---|---|---|---|
| < 82.0 | < 79.7 | Normal activities | At least three separate rest breaks each hour, minimum 3 min each | None listed |
| 82.2 – 86.9 | 79.9 – 84.6 | Use discretion for intense or prolonged exercise | At least three separate rest breaks each hour, minimum 4 min each. Yellow: a 5-minute water break every 30 minutes | None listed |
| 87.1 – 90.0 | 84.7 – 87.6 | Maximum practice time is 2 h | At least four separate rest breaks each hour, minimum 4 min each. Orange: an 8-minute water break every 30 minutes | Helmet, shoulder pads, and shorts during practice |
| 90.1 – 91.9 | 87.8 – 89.6 | Maximum practice time is 1 h | 20 min of rest breaks distributed throughout the hour. Red: 20 minutes of practice, a 20-minute water break, 20 minutes of practice | No protective equipment; no conditioning activities |
| > 92.1 | > 89.8 | No outdoor workouts. Delay practice until a cooler WBGT is reached | — | — |
Source: NIAA 2026-2027 Heat Acclimatization – Heat Illness Guidelines, Environmental Monitoring and Activity Modification/Cancellation and WBGT Hydration Breaks, checked 15 Oct 2026. Ranges as printed. Category 1 bands: < 76.1, 76.3 – 81.0, 81.1 – 84.0, 84.2 – 86.0, > 86.2. If the WBGT rises into the third zone during practice, football players may continue in football pants without changing to shorts. During water breaks helmets come off and coaches may not have contact with athletes; break time counts toward practice time.
Where does Flash fit?
Flash is a forecast for planning, not an on-site meter: the NIAA zones apply to the WBGT your designated person reads at your 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 zones for your category. 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 NIAA's (Category 3)
6:30 pm · The reading that decides the day
The zone you land in sets the clock, the water breaks, the pads and the tub.
Flash 6-hour WBGT outlook for the practice field: 86 by 3 pm, into 87.1–90.0 by 4 pm. The athletic director flags the football session.
Decision: run at 4 pm under the 2-hour cap with an 8-minute water break every 30 minutes, or push to 6:30 pm. The AD pushes. The bus, the trainers and the parents hear now, not at 3:45.
The designated person reads 84.6 at the monitoring site, the yellow zone. A 5-minute water break every 30 minutes, helmets off, and the cold-water tub set up by the field. The reading is recorded.
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 NIAA guidelines have all environmental monitoring recorded and stored for reference. Keep these together so a question from the NIAA, the district or a parent is answered from one folder.
- WBGT readings with times, every 30 minutes from the scheduled practice time, and the zone and modification each one triggered.
- Your region category, the designated monitoring site, and who the designated, trained person is.
- Any day the heat index was used as the back-up, and why the WBGT device was unavailable.
- The cold-water immersion tub set-up for practices above the green zone, and the emergency plan around it.
- 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)
- 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 Carolina (SCHSL)
- South Dakota (SDHSAA)
- Utah (UHSAA)
- Vermont (VPA)
- Virginia (VHSL)
- Washington (WIAA)
- Wisconsin (WIAA)
Sources
- NIAA — 2026-2027 Heat Acclimatization – Heat Illness Guidelines. WBGT zones by region category, monitoring, water breaks, acclimatization, cold-water immersion. Checked 15 Oct 2026.niaa.com/sports/fball/2026-2027_NIAA_Heat_Acclimatization_-_Heat_Illness_Guidelines_Document.pdf (opens in a new tab)
- Grundstein et al., Regional heat safety thresholds for athletes in the contiguous United States, Applied Geography, 2015. The region-category map the NIAA reproduces.ksi.uconn.edu/wp-content/uploads/sites/1222/2018/08/RegionalWBGT_2015_AppliedGeography.pdf (opens in a new tab)
NIAA documents are published at niaa.com (opens in a new tab).
Frequently asked
No. The NIAA zones apply to the WBGT your designated person reads at the school's monitoring site. Flash's 6-hour outlook tells you where that reading is heading — a scheduling tool, not a compliance instrument.
The NIAA has schools follow the guidelines for the region they are located in, using the regional heat-safety map it reproduces from Grundstein et al. The same zones are printed for Categories 1, 2 and 3.
The heat index may be used as a temporary back-up. From a heat index of 105, football practices drop equipment in steps with water breaks at least every 20 minutes; above 120, all outdoor practices are cancelled or moved indoors.
Yes, for all sports. During days 1–5 of formal practice, athletes take part in no more than one practice a day and no more than 3 hours of practice in total, with a 1-hour walk-through allowed after a 3-hour recovery.