Illinois IHSA Heat Policy and WBGT Guidelines
The Illinois High School Association (IHSA) sets heat limits for high school athletics by Wet Bulb Globe Temperature (WBGT). Here are the activity limits at each level, and how Sports Safe applies them to your fields.
Outdoor practice stops
90.0°F WBGT and above
Illinois WBGT activity chart
No Flag
Under 80.0°F
Practice limit: None stated
Water always available, in as much quantity as athletes want. Optional water breaks every 30 minutes for 10 minutes, coordinated with contest officials. Ice-down towels available for cooling. Monitor athletes carefully.
Green Flag (low)
80.0 to 84.5°F
Practice limit: None stated
Water always available, in as much quantity as athletes want. Optional water breaks every 30 minutes for 10 minutes. Provide cooling stations such as ice towels. Reduce time outdoors and consider postponing activity to later in the day. Recheck conditions every 30 minutes, or sooner if heat stress is suspected.
Equipment: Contact sports: helmets and other equipment removed while not involved in contact.
Yellow Flag (moderate)
84.6 to 87.5°F
Practice limit: 2 hours
Maximum 2 hours of training or practice in this range. At least four 4-minute breaks each hour, or a 10-minute break every 30 minutes. Cooling stations before, during and after activity. Reduce outdoor time, and indoor time where air conditioning is unavailable. Consider postponing to later in the day or another day (IHSA Administration approval required).
Equipment: Contact sports: helmets and equipment removed if not needed for the activity. If equipment is necessary for safety, suspend activity.
Red Flag (high)
87.6 to 89.9°F
Practice limit: 1 hour
Maximum 1 hour of training or practice in this range. At least four 4-minute breaks each hour, or a 10-minute break every 30 minutes. Cooling stations before, during and after activity. Reduce outdoor time, and indoor time where air conditioning is unavailable. Consider postponing to later in the day or another day (IHSA Administration approval required).
Equipment: Contact sports: helmets and equipment removed if not needed for the activity. If equipment is necessary for safety, suspend activity.
Black Flag (extreme)
90.0°F and above
Practice limit: No outdoor practice
No training or competition. Cancel or postpone activity to a cooler time of day.
| WBGT | Level | Practice limit | What the chart says |
|---|---|---|---|
| Under 80.0°F | No Flag | None stated | Water always available, in as much quantity as athletes want. Optional water breaks every 30 minutes for 10 minutes, coordinated with contest officials. Ice-down towels available for cooling. Monitor athletes carefully. |
| 80.0 to 84.5°F | Green Flag (low) | None stated | Water always available, in as much quantity as athletes want. Optional water breaks every 30 minutes for 10 minutes. Provide cooling stations such as ice towels. Reduce time outdoors and consider postponing activity to later in the day. Recheck conditions every 30 minutes, or sooner if heat stress is suspected. Equipment: Contact sports: helmets and other equipment removed while not involved in contact. |
| 84.6 to 87.5°F | Yellow Flag (moderate) | 2 hours | Maximum 2 hours of training or practice in this range. At least four 4-minute breaks each hour, or a 10-minute break every 30 minutes. Cooling stations before, during and after activity. Reduce outdoor time, and indoor time where air conditioning is unavailable. Consider postponing to later in the day or another day (IHSA Administration approval required). Equipment: Contact sports: helmets and equipment removed if not needed for the activity. If equipment is necessary for safety, suspend activity. |
| 87.6 to 89.9°F | Red Flag (high) | 1 hour | Maximum 1 hour of training or practice in this range. At least four 4-minute breaks each hour, or a 10-minute break every 30 minutes. Cooling stations before, during and after activity. Reduce outdoor time, and indoor time where air conditioning is unavailable. Consider postponing to later in the day or another day (IHSA Administration approval required). Equipment: Contact sports: helmets and equipment removed if not needed for the activity. If equipment is necessary for safety, suspend activity. |
| 90.0°F and above | Black Flag (extreme) | No outdoor practice | No training or competition. Cancel or postpone activity to a cooler time of day. |
Key points
- Water must be freely available at every level, in as much quantity as athletes want.
- Cooling stations, such as ice towels, are required from Green upward, and before, during, and after activity from Yellow upward.
- From Yellow upward: at least four 4-minute breaks each hour, or a 10-minute break every 30 minutes. Practice is limited to 2 hours at Yellow and 1 hour at Red.
- Recheck conditions every 30 minutes at every level, or sooner if heat stress is suspected. Postponing to another day requires IHSA approval.
Common questions
- At what WBGT does outdoor practice stop in Illinois?
- Using the IHSA heat policy, Sports Safe stops outdoor practice at 90.0°F WBGT.
- How long can practice last at each heat level in Illinois?
- Under the IHSA heat policy, the practice time limits are: Yellow Flag (moderate), 84.6 to 87.5°F: 2 hours; Red Flag (high), 87.6 to 89.9°F: 1 hour. Levels not listed have no time limit stated, and at the top level outdoor practice stops.
- Does Sports Safe use the heat chart for Illinois automatically?
- Yes. Sports Safe uses the IHSA chart for fields in Illinois. You can choose a different chart for any field in its settings.
How Sports Safe uses the Illinois chart
Sports Safe estimates WBGT for each of your fields from current weather, checks it against this chart, and alerts you when a field moves into a stricter level. On the Organization plan, coaches can keep a timestamped log of meter readings and the actions taken.
An app estimate supports your decisions but is not a WBGT meter. Where your association requires readings from an approved instrument, use one for the reading of record.
Source
Summarized from the IHSA's published heat policy. View the source. Last reviewed October 3, 2026.
Sports Safe is not affiliated with or endorsed by the Illinois High School Association. Policies change, so always confirm the current rules with your association and follow your school's emergency action plan.