On this page · 8 sections
What does the policy require?
The IHSAA, IGHSAU, IHSMA and IHSSA, guided by the Iowa Sports Medicine Advisory Committee, approved the WBGT as the measurement practice and device for heat and humidity at practices and contests. Its use is required throughout the calendar year when the ambient temperature is above 80 degrees, indoors or outdoors. Appendices add rules for middle school and for specific activities, including football, marching band and cheer.
WBGT is measured every 30 minutes where the activity is held, ideally by the same person throughout the event. The reading at the start of practice or a contest sets the lowest band to follow; if the WBGT climbs into a higher band, that band’s modifications apply. Participants always have unrestricted access to water, and schools should have an exertional heat illness emergency action plan.
Reading cadence
Every 30 minutes where the activity is held, by the same person throughout the event.
Only up, never down
The start-of-practice reading sets the lowest band. A higher reading moves you to that band’s modifications.
Cold-water immersion
Available from 79.8. Appendix B: a 50-gallon tub with water cooled to 35–59°F.
Year-round
Required whenever the ambient temperature is above 80 degrees, indoors or outdoors, all year.
The Iowa WBGT threshold table
Five bands for grades 9–12, read in degrees Fahrenheit from the WBGT device. The row colour follows the Flash alert scale your athletic trainers already see in the app.
| WBGT (°F) | Activity limit | Rest breaks | Equipment |
|---|---|---|---|
| Under 79.7 | Normal activities | 3 separate rest/water breaks (3-5 minutes each) / hour | None listed |
| 79.8 – 84.6 | Use discretion for intense / prolonged practice. Monitor at-risk athletes closely. Cold water immersion available | 3 separate rest/water breaks (4-6 minutes each) / hour | None listed |
| 84.7 – 87.6 | Maximum practice time is 2 hours. Monitor at-risk athletes closely. Cold water immersion available. CONTESTS: Implement additional/extended timeouts for rest/water breaks | 4 separate rest/water breaks (4-6 minutes each) / hour | Reduce equipment to partial uniform. Remove all additional equipment if conditioning (football) |
| 87.7 – 89.7 | Maximum practice time is 1 hour. No conditioning allowed. Monitor athletes closely. Cold water immersion available. CONTESTS: Consider moving start times earlier or postponing; Implement additional/ extended timeouts for rest/water and shade | There must be 20 minutes of rest breaks distributed throughout the one hour of practice | Reduce equipment to out of uniform |
| Over 89.7 | No (outdoor) activities. Cancel or delay outdoor practices / contests until lower WBGT is recorded | — | — |
Source: IHSAA / IGHSAU / IHSMA / IHSSA WBGT Heat Modification Policy, grades 9–12 table (Region 2), iahsaa.org, checked 15 Oct 2026. Ranges as printed. If the WBGT rises into 84.7–87.6 during practice, players may continue practicing in football pants. Appendix C sets football at 84.7–87.6 to helmets, shoulder pads and shorts only, and at 87.7–89.7 to shorts, t-shirts and footwear only.
Where does Flash fit?
Flash is a forecast for planning, not an on-site meter: the Iowa policy runs on the WBGT measured where the activity is held. 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 Iowa 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 Iowa policy’s (grades 9–12)
6:30 pm · The reading that decides the day
The start-of-practice band is the floor; it only goes up from there.
Flash 6-hour WBGT outlook for the 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 partial uniform, 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, which is now the floor for the session. Three 4–6 minute breaks per hour and the cold-water tub go on the plan.
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 policy does not set a records rule. Keeping these together still means a question from the associations, the district or a parent is answered from one folder.
- WBGT readings with times, every 30 minutes where the activity is held, and who took them.
- The start-of-practice band and any later band change, with the modifications each one triggered.
- The exertional heat illness emergency action plan, including the cold-water immersion tub.
- Activity-specific rules followed from the appendices: football, marching band, cheer, middle school.
- 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)
- 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
- IHSAA / IGHSAU / IHSMA / IHSSA — Wet Bulb Globe Thermometer (WBGT) Heat Modification Policy. Grades 9–12 thresholds, reading cadence, year-round scope. Checked 15 Oct 2026.iahsaa.org/wp-content/uploads/2024/09/WBGT-Heat-Modification-Policy.pdf (opens in a new tab)
- IHSAA — Health & Safety resources, iahsaa.org, linking the policy, Appendices A–E and the WBGT temperature guidelines sheet. Checked 15 Oct 2026.iahsaa.org/resources/health-safety/ (opens in a new tab)
IHSAA / IGHSAU documents are published at iahsaa.org (opens in a new tab).
Frequently asked
No. The Iowa policy runs on the WBGT measured where the activity is held. Flash's 6-hour outlook tells you where that reading is heading — a scheduling tool, not a compliance instrument.
No. The reading at the start of practice or a contest sets the lowest band to follow. If the WBGT rises into a higher band, that band’s modifications apply.
Yes. The policy covers practices and contests, adds contest timeouts from 84.7, and its appendices cover middle school, football, marching band, cheer and other activities.