State Weather Policies > Illinois State Weather Policies

Illinois State Weather Policies (2024-2025)

Heat Stress Policy and Activity Recommendations

What are the IHSA Heat Stress Activity Guidelines for 2024/2025?

WBGT Recommended Activity Guidelines

WBGT Activity Guidelines

The following Wet Bulb Globe Temperature requirements are based on requirements by the Illinois High School Association (IHSA) for 2024-2025 and are for indoor and outdoor practices.  These requirements are the minimum standards that all Illinois High School Association (IHSA) member schools must follow during indoor and outdoor athletic activities. Schools with more restrictive heat stress guidelines are not expected to modify pre-existing guidelines to meet this policy:

  • Temperature and humidity readings will be taken at the activity site 30 minutes before and every 30 minutes after the start, using a Wet Bulb Globe Thermometer.
  • Readings must be recorded and kept by the school administration, who may delegate this task.
  • Ensure the availability of cooling stations, including shade, ice towels, misting fans, etc., for use before, during, and after activity.
  • Provide abundant water access, allowing athletes to drink as much water as they wish, with water readily available at all times.
Illinois WBGT Zone and Heat Acclimatization

Illinois WBGT Class 2 & 3 Zones

Illinois is divided into Class 2 and 3 zones, with each zone providing specific recommendations to adjust activity levels and keep athletes safe. The chart above outlines the activity guidelines relative to both zones. Here’s what the IHSA has mandated:

  • Every School Must have a Cooling Zone: All schools must have cooling zones where the WBGT is 80°F or higher.
  • Cooling zones must have cold-water immersion options for rapid cooling.
  • Coaches must provide unlimited access to water throughout practice. Rest breaks should focus on rehydration and rest only, with no activity.
  • In cases of potential Exertional Heat Stroke (EHS), schools must be equipped to activate EMS and provide rapid whole-body cooling using Cold Water Immersion (CWI).
  • Best practices should be carried out by licensed personnel, with cooling initiated until advanced medical help arrives.

How Can Perry Weather Help?

WBGT Monitoring System

Precise on-site WBGT monitoring

For athletic trainers and directors prioritizing athlete safety, Perry Weather offers precise on-site wet bulb globe temperature monitoring.


Guide your coaches and staff in taking the right actions with hyper-local WBGT monitoring and alerts tailored to your heat stress policies.

  • Accurate WBGT offers a more precise understanding of real-world conditions than heat index, ensuring safety and informed decision-making for all outdoor activities.
  • Automatic WBGT measurements are instantly recorded and stored, ensuring you stay compliant without the tediousness and potential errors of traditional manual methods.
  • We translate data into practical steps based on heat stress policies and local regulations – from hydration reminders to activity adjustments, we ensure safety first.
Automated Mobile Alerts

Automated heat stress policy based alerts

Automatic instructive alerts and warnings are triggered based on your policies, keeping you compliant and confident in your decision-making so everyone on your staff knows what to do when WBGT levels are high.

  • Automated Warnings: Push notifications and text message alerts with automatic action instructions once WBGT threshold is breached
  • Custom Quiet Times: Pause notifications during weekends or nighttime, ensuring disturbance-free periods for when practices and games aren’t taking place
  • Configurable Settings: Configure specific user and warnings settings that fit your organization’s needs
Proactive Heat Stress Updates

Predictive Heat Stress Warnings

Get heat and WBGT risk updates based on your policies, so you’re not caught by surprise and are able to adjust outdoor activities accordingly.

  • Set customized alerts to be notified when WBGT levels reach critical thresholds, ensuring timely action to protect athletes from heat-related illnesses.
  • Our team stays up-to-date on evolving state regulations to help schools and athletic trainers implement heat stress guidelines effectively.

Heat Stress & WBGT FAQs

What is Wet Bulb Globe Temperature (WBGT)?

The WBGT is a comprehensive measure that combines air temperature, relative humidity, radiant heat, and air movement to assess heat stress conditions. Read more about WBGT here.

What is the difference between the Wet Bulb Globe Temperature and the Heat Index?

Wet bulb globe temperature in a nutshell is a more in-depth heat stress measurement taking into account more of the environment (Direct sunlight, water vapor capacity, cloud coverage, etc.). Read more about the differences between WBGT and the heat index here.

What is a Heat Illness?

There are two main ways heat illness can strike:
1. Classic Heat Illness: This is caused by your environment’s impact on your body’s ability to cool down. Think high temperatures, humidity, direct sun, and no breeze.
2. Exertional Heat Illness (EHI): This one focuses on your own internal heat production. It can happen even in mild weather if you push yourself too hard.

What is the science behind WBGT?

Wet bulb globe temperature involves measuring three temperatures: dry bulb, wet bulb, and globe. Read more here.

What is the difference between Heat Stress and Heat Illness?

Imagine heat stress as a warning light on your body’s dashboard. If heat stress isn’t addressed, it can progress to heat illness. This is a medical emergency where the body can no longer cool itself down effectively. It can be life-threatening if not treated promptly. Read more here.

How can I measure the WBGT? What is the best way to measure the wet bulb globe temperature?

To measure WBGT, use a scientifically approved WBGT meter. The best way to measure it is by using Perry Weather’s advanced weather monitoring platform.

IHSA Lightning Safety Recommendations

When to Suspend Play?

The following guidelines are based on recommendations by the IHSA.

Activities must be postponed or suspended if signs of a thunderstorm are imminent before or during an activity or contest. Here’s what to do during a thunderstorm:

  • When thunder is heard, or lightning is seen, immediately suspend play for at least 30 minutes and seek shelter in a designated safe shelter.
  • Once play has been suspended, wait at least 30 minutes after the last thunder is heard or lightning is witnessed before resuming play.
  • Any subsequent thunder or lightning after the beginning of the 30-minute count will reset the clock and another 30-minute count should begin.
  • If available, use lightning detectors that can support decisions.
  • Distant storms can produce visible flashes without audible thunder. If flashes are low on the horizon and no thunder is heard, continuing activity may be safe. However, prioritize safety and err on the side of caution.

Lightning Safety Recommendations

Nearly all lightning-related injuries occur between May and September between the hours of 10:00 AM. and 7:00 PM. Therefore, the greatest concern for injuries in an outdoor contest appears to be during that time, though it can happen any time of year.The following guidelines are based on recommendations by the IHSA:

  • If thunder is heard, or a cloud-to-ground lightning bolt is seen, immediately suspend play and take shelter.
  • The National Severe Storms Laboratory (NSSL) recommends waiting at least 30 minutes after the last flash of lightning or sound of thunder before resuming activities.
  • Ensure all involved parties, including local managers, competing schools, and contest officials, are briefed on the suspension protocol before tournaments or events.
  • Communicate any portable devices or specific policies from competing schools to the tournament manager beforehand.
  • Tournament managers must know the policies of each school assigned to their tournament or event prior to its start.

How Can Perry Weather Help?

Lightning Alerts & Safety

Instantly Tailor Alerts to Your Lightning Safety Policies

Perry Weather’s lightning detection and alerts system gives you clear, actionable instructions aligned with your lightning safety policies.

  • We’ll notify you as soon as lightning is detected with automated alerts. We guide you through immediate actions, keeping your athletes safe and practices on track.
  • Automatic alerts and real-time data for informed decision-making during critical weather events.
Lightning Countdown Timer

Know When It’s Safe to Resume Activities

Know exactly when it’s safe to step out after a lightning strike with Perry Weather’s lightning countdown timers.

  • When a lightning strike is detected nearby, Perry Weather initiates a countdown until given the all-clear and resuming outdoor activities.
  • The timer resets with each subsequent strike, ensuring adherence to lightning safety protocols before resuming activities
  • Stay a step ahead with advanced radar and predictive lightning risk management for confident event planning and adaptive scheduling.
Integrated Outdoor Warnings and Siren

Outdoor Warning System

Get custom PA alerts and audible alarms with our lightning warning system.

  • Instantly broadcast alerts and safety messages automatically across your campus – no matter the weather conditions.
  • Strobe lights, loud alarms, and text-to-speech make sure you won’t miss lightning alerts.
  • It works even during power outages, ensuring continuous safety without needing a direct power source.

Lightning FAQs

What do I do if lightning strikes?

  • Activate local Emergency Management Service.
  • If necessary, carefully move the victim to a safer location.
  • Assess airway, breathing, and circulation; initiate CPR if needed.
  • Check for and treat hypothermia, shock, fractures, and burns.

What do I NOT do when lightning strikes?

  • Do not shower, bathe, or use landline phones inside a safe shelter (cell phones are OK).
  • Avoid being the highest point in an open field, or near the tallest object.
  • Stay away from any open water.
  • Do not seek shelter under or near trees, flagpoles, or light poles.
  • Do not lie flat on the ground.

What is a Safe Shelter?

A safe shelter is any frequently inhabited building with four solid walls (not a dugout), electrical and telephone wiring, and plumbing, which aid in grounding the structure.

Where Do I Go When Lightning Approaches?

  • Designate a safe shelter for each venue.
  • All individuals have the right to leave an athletic site to seek a safe structure if they feel in danger of impending lightning.
  • As a secondary option, a fully enclosed vehicle with a metal roof and completely closed windows provides safety from lightning.
  • Do not touch any part of the vehicle’s metal framework during a thunderstorm.

Can a player who has been struck by lightning be safely touched by others?

Yes. Lightning victims do not carry a residual electrical charge. However, prioritize checking for injuries and call emergency services immediately.

Who is responsible for enforcing lightning safety protocols during practices or games?

Responsibilities may vary, but typically coaches, athletic trainers, and officials share the responsibility for monitoring weather conditions and enforcing safety procedures.

What if there are no readily available shelters nearby?

Some policies allow for designated “safe havens” under sturdy structures like bleachers (away from metal supports) or inside enclosed vehicles with the windows rolled up. However, this is a last resort.

Here’s How Schools Are Addressing Weather Policies Using Perry Weather

Watch how schools across the country are using Perry Weather to comply with state weather policies and keep their campuses safe.

Learn More About Crafting Weather Policies

Get a Free Two Week Trial

Take Perry Weather for a test drive with a two-week free trial. Get started today!