On this page · 8 sections
What does the HHSAA require?
The HHSAA policy, prepared with the Hawaii Athletic Trainers Association and the HHSAA Sports Medicine Advisory Committee, applies to all sports. It covers practices and scrimmages, which count as practices, but not games. Each school designates an individual to monitor temperature and humidity.
Best practice under the policy is a wet bulb globe thermometer, such as a Kestrel heat monitor. To allow for the equipment schools have, each school may choose either the WBGT chart or a heat index chart, built from a sling psychrometer reading, to decide practice modifications or cancellations. Readings are taken before practice starts to decide what practice is permissible, and again during practice if temperature and humidity are climbing.
Reading cadence
Before practice starts, to decide what practice is permissible. More readings if temperature and humidity rise during practice.
WBGT or heat index
Each school chooses one chart. A WBGT monitor is best practice; a sling psychrometer and the heat index chart is the alternative.
Designated monitor
Each school designates the individual who takes the readings. Placement: near where athletes spend the most time, where the device is safe.
Acclimatization
A 14 calendar day acclimatization period from the first day of the HHSAA start date for the sport.
The HHSAA WBGT threshold table
Five bands, read in degrees Fahrenheit from the WBGT monitor, for schools that use the WBGT chart. The row colour follows the Flash alert scale your athletic trainers already see in the app.
| WBGT (°F) | Activity limit | Rest breaks | Football equipment |
|---|---|---|---|
| < 82 | Normal activities | At least 3 separate rest breaks each hour of minimum of 3 minutes | None listed |
| 82 – 86.9 | Use discretion for intense or prolonged exercise; watch at-risk players carefully | At least 3 separate rest breaks each hour of a minimum of 4 minutes | None listed |
| 87 – 89.9 | Maximum practice time is 2 hours | At least 4 separate rest breaks each hour of a minimum of 4 minutes | Helmets, shoulder pads, and shorts during practice; all protective equipment removed for conditioning |
| 90 – 92 | Maximum length of practice is one hour; no conditioning activities | 20 minutes of rest breaks provided during the hour of practice | No protective equipment may be worn during practice |
| > 92.1 | No outdoor workouts. Cancel exercise; delay practices until a cooler WBGT reading occurs | — | — |
Source: HHSAA Heat Acclimatization and Practice Policy, May 2017, Monitoring of Temperature and Humidity, WBGT chart (p. 8; file revised 7-11-17, hhsaa.org governing documents), checked 15 Oct 2026. Ranges as printed. Schools that use the heat index chart instead follow its five levels, from Safe under 80°F to Danger at 105°F and above, where all outside activity stops.
Where does Flash fit?
Flash is a forecast for planning, not an on-site meter: HHSAA modifications follow the reading your designated person takes at practice. 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 HHSAA 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 HHSAA's
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 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 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.
The school's designated monitor reads 84.8 before practice, the 82–86.9 band. Three 4-minute breaks per hour go on the plan and at-risk players are watched closely.
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 HHSAA policy puts the monitoring on a designated person at each school. Keeping the readings and decisions together means a question from the HHSAA, the league or a parent is answered from one folder.
- Readings with times — before practice, and again as temperature and humidity rise — and whether the school uses the WBGT or the heat index chart.
- The band each reading fell in and the decision it triggered: practice length, rest breaks, football equipment.
- Who the designated monitor is, and the instrument used: a WBGT monitor or a sling psychrometer.
- The written, practiced emergency action plan, with the tub, ice and cooling location ready.
- 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)
- 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 Carolina (SCHSL)
- South Dakota (SDHSAA)
- Utah (UHSAA)
- Vermont (VPA)
- Virginia (VHSL)
- Washington (WIAA)
- Wisconsin (WIAA)
Sources
- HHSAA — Heat Acclimatization and Practice Policy, May 2017 (file revised 7-11-17). WBGT and heat index charts, monitoring, acclimatization, FAQs. Checked 15 Oct 2026.hhsaa.org/assets/content/resources/governing_documents/Heat-Acclimatization-Revised-7-11-17.pdf (opens in a new tab)
HHSAA documents are published at hhsaa.org (opens in a new tab).
Frequently asked
No. HHSAA modifications follow the reading the school's designated person takes at practice. Flash's 6-hour outlook tells you where that reading is heading — a scheduling tool, not a compliance instrument.
Yes. Each school may choose either the WBGT chart or the heat index chart. A wet bulb globe thermometer is best practice; a sling psychrometer gives the temperature and humidity for the heat index.
No. The HHSAA says games have enough built-in rest and hydration opportunities, and officials may extend time-outs or halftimes. The policy does apply to scrimmages, which count as practices.