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An empty floodlit high school football field at dusk with heat haze over the turf, the setting IHSA WBGT practice limits govern at Illinois schools

State heat policy · Illinois (IHSA) · Verified 15 Oct 2026

Illinois high school heat policy: IHSA WBGT thresholds, practice limits, and how to plan around them

The IHSA's Managing Heat and Heat Illness policy sets minimum standards every member school must follow: an on-site WBGT reading before and during activity, five bands that decide practice length, rest breaks and football equipment, and cold-water immersion ready from 80. Here are the bands as the IHSA prints them, what to keep on file, and how a 6-hour WBGT outlook lets you move practice instead of cancelling it.

Flash Meteorology Desk · Checked against IHSA Managing Heat and Heat Illness (ihsa.org) · Updated 15 Oct 2026 · 7 min read

WBGT outlook · Field B · 6 hours

12:58

84.682921 pm2 pm3 pm4 pm5 pm6 pm
  • 4 pm · 85.6 — in 84.6–87.5
  • Under 84.6 after 5:00

Move practice to 5:30 — the on-site reading stays the compliance record.

Illustrative example · Not live weather
On this page · 8 sections

What does the IHSA require?

The policy sets minimum standards for all athletic activities and competitions, outdoors and in indoor facilities that are not air-conditioned. Schools with stricter rules of their own keep them. Tournament managers, or their designees, use the same guidelines at every IHSA state series event once the WBGT is above 80, and decisions to suspend and resume activity follow them.

A Wet Bulb Globe Thermometer is required. Readings are taken at the site 30 minutes before the activity starts and at least every 30 minutes after, recorded in writing and kept on file by the tournament manager or the host school administration. Schools provide cooling stations such as shade, ice towels and misting fans, unlimited water, and a whole-body cooling setup that is ready for immediate use at a WBGT of 80 or above.

  • Reading cadence

    At the activity site, 30 minutes before the start, then at least every 30 minutes. A Wet Bulb Globe Thermometer is required.

  • Records on file

    Readings recorded in writing and kept by the tournament manager or the host school administration.

  • Cold-water immersion

    Ready for immediate use at a WBGT of 80 or above; readily available below 80. Cool first, transport second.

  • Contests

    From 84.6, no new contest may start. A contest already under way may finish with the required breaks.

The IHSA WBGT threshold table

Five bands, read in degrees Fahrenheit from the on-site WBGT device: one table for the whole state. The row colour follows the Flash alert scale your athletic trainers already see in the app.

IHSA WBGT activity guidelines for Illinois high school sports: five bands from under 79.9 to over 89.9 °F with practice-length, rest-break, football-equipment and cold-water immersion rules
WBGT (°F)Activity limitRest breaksFootball equipment
Under 79.9Normal ActivitiesProvide at least three separate rest breaks each hour with a minimum duration of 3 min each during the workoutNone listed
80.0 – 84.5Use discretion for intense or prolonged exercise. Cold Water Immersion must be availableProvide at least three separate rest breaks each hour with a minimum duration of 5 min eachNone listed
84.6 – 87.5Maximum practice time is 2 h. Contests may conclude if the temperature moves to orange mid-game with the required breaks provided. No new contests may be started if the temperature is in this range. Cold Water Immersion must be availableFor All Sports: There must be 20 min of rest breaks distributed throughout each hour of practiceFor Football: players are restricted to helmet, shoulder pads, and shorts during practice
87.6 – 89.9Maximum practice time is 1 h. Cold Water Immersion must be available. Consider postponing games or practices until a cooler time of dayFor All Sports: There must be 20 min of rest breaks distributed throughout the hour of practiceFor Football: No protective equipment may be worn during practice, and there may be no conditioning activities
Over 89.9No outdoor workouts. Delay practice until a cooler WBGT is reached——

Source: IHSA Managing Heat and Heat Illness, Table 1 (Cat 2), as linked from the IHSA Sports Medicine pages (ihsa.org), verified 15 Oct 2026. Ranges as printed; all readings as measured by a WBGT device. If the WBGT rises into 84.6–87.5 during practice, football players may continue in football pants without changing to shorts.

Where does Flash fit?

Flash is a forecast for planning, not an on-site meter: IHSA compliance uses the reading from your Wet Bulb Globe Thermometer, recorded before and during activity. 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 IHSA 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 method

  • Return 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 IHSA's

An empty high school practice field under a hazy hot sun with a shade canopy and water coolers on the sideline, the setting for an IHSA WBGT planning day in Illinois

6:00 pm · The reading that decides the day

The band you land in sets the clock, the breaks, the pads and the tub.

  1. Flash 6-hour WBGT outlook for the practice field: 83 by 3 pm, into 84.6–87.5 by 4 pm. The athletic director flags the football session.

  2. Decision: run at 4 pm under the 2-hour cap with 20 minutes of breaks each hour, or push to 6:30 pm. The AD pushes. The bus, the trainers and the parents hear now, not at 3:45.

  3. On-site WBGT reading 30 minutes before practice: 82.9, the 80.0–84.5 band. Three 5-minute breaks per hour go on the plan, the cold-water tub is ready and the reading is written into the file.

  4. Flash lightning alert: a strike is predicted inside the site radius within the next 60 minutes. The field clears.

  5. Last strike inside the radius. Flash starts the all-clear timer.

  6. All clear. Practice resumes; the alert log records who was warned, when, and when play returned.

What does the athletic director keep on file?

The IHSA requires readings to be recorded in writing and kept by the tournament manager or the host school administration. Keep these together so a question from the IHSA, the district or a parent is answered from one folder.

  • WBGT readings with times: 30 minutes before the activity, then at least every 30 minutes.
  • The band each reading fell in and the decision it triggered: practice length, rest breaks, football equipment, whether a contest started.
  • The written emergency plan for exertional heat stroke, coordinated with local EMS, and the drills run on it.
  • The cold-water immersion setup and who is trained to use it: a licensed athletic trainer, designated healthcare provider or EMS provider.
  • 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.

Heat haze over an open field at midday, the conditions each state association's WBGT policy sets practice limits for

State by state

Same instrument, different bands — the WBGT forecast travels with you.

All state heat policies

Sources

  1. IHSA — Managing Heat and Heat Illness, Wet Bulb Globe Temperature, with Table 1 and cooling methods. Thresholds, reading cadence, records, cold-water immersion. Verified 15 Oct 2026.archive.ihsa.org/documents/sportsMedicine/current/Managing%20Heat%20and%20Heat%20Illness.pdf (opens in a new tab)

IHSA documents are published at ihsa.org (opens in a new tab).

Frequently asked

No. The IHSA requires a Wet Bulb Globe Thermometer reading at the activity site, recorded in writing. Flash's 6-hour outlook tells you where that reading is heading — a scheduling tool, not a compliance instrument.

Thirty minutes before the activity starts, then at least every 30 minutes after it starts, at the site of the activity. Record each one in writing.

Yes. The policy covers practices and competitions. From 84.6, no new contest may start, though one already under way may finish with the required breaks. IHSA state series events use the same guidelines once the WBGT is above 80.

At a WBGT of 80 or above, the cooling setup must be ready for immediate use. Below 80, it should be readily available.

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