Outdoor Events and Extreme Heat
Climate change is making summers longer and hotter, leading to more frequent extreme heat events. The hotter the temperature and the more time people spend outside, the greater the risk of heat-related illness or death.
If you are planning an outdoor event during the warmer months, be prepared to protect yourself and attendees from hot weather.
Assess Risk
Consider what the planned activities are. As temperatures get hotter, outdoor physical activity can increase the risk of heat-related illness. If participants will be physically active, such as dancing or running, it is more important to prepare for the heat. Heat preparedness is less important if participants will be doing water activities such as swimming or less physically intense activities.
If participants or staff are people at higher risk of heat-related illness, you need to take precautions to protect them in hot weather. Those at greatest risk of heat-related illness at an outdoor event include people:
- With chronic medical conditions, such as heart, lung or kidney disease, and diabetes
- With mental health, cognitive or developmental conditions, such as dementia or schizophrenia
- Who are pregnant
- Age 60 and over and children age 4 and under
- Who take medications that make it difficult for the body to stay cool
- Who are using drugs or alcohol
- With limited mobility
Time and Place
Depending on the activities and participants, consider heat when selecting the time and place for your event.
Holding the event during cooler parts of the day—before 10 a.m. or after 6 p.m.—can protect from the heat. The sun’s rays are the strongest between 10 a.m. and 4 p.m., and the temperature is highest between 3 to 6 p.m. on most days.
Selecting a heat-friendly location can lessen the heat’s impact. Things to consider:
- An area with a natural surface such as grass, dirt or sand will be cooler than one with an asphalt or other impermeable (human-made) surface, which can increase temperatures and retain heat into the evening.
- If the sun will still be out during your event, choose a space where shade is available, or where shade can be created, sufficient to provide relief in high temperatures.
- Areas where misting stations and indoor, air-conditioned spaces could be accessed or added are ideal in hot weather.
Reduce Impacts from Heat
As the event day approaches, monitor the forecast and get ready to implement protective measures. To prepare for the event, you should:
- Check the forecasted heat index for the day of the event. The heat index is what the temperature feels like to a person when the relative humidity is combined with the air temperature. High humidity makes it harder for us to regulate our temperature by sweating, making temperatures feel hotter.
- If the heat index is forecast to be 85°F or above, prepare to take steps to keep participants safe from the heat by reviewing the event day recommendations listed below.
- Consider whether you will shift activities, timing, or location, if possible and depending on the forecast.
- Prepare messages you may want to provide participants about steps you are taking to prepare for the heat.
Protect Participants and Staff During the Event
Depending on how hot it is expected to be, there are steps you can take to lessen the impacts of heat and make your event a success.
Heat Index of 85 Degrees F to 94 Degrees F
- Communicate with participants, including via on-site signs, about the importance of drinking lots of water, keeping cool and other outdoor heat safety tips.
- Make water accessible to all participants and anyone working at the event.
- Encourage attendees to drink water or non-caffeinated sports drinks and to eat to replenish electrolytes.
- Encourage the use of hats and sunscreen.
Heat Index of 95 Degrees F to 99 Degrees F
Follow recommendations from the previous heat level and:
- Message frequently about hydration, shade, keeping cool and heat risk.
- Warn attendees and staff about symptoms and increased risk of heat exhaustion and heat stroke.
- Increase availability of free drinking water, and limit or eliminate any sale or consumption of alcohol.
- Encourage attendees to take breaks from dancing and physical activity and sun exposure.
- Designate areas with shade, air-conditioned space or other cooling relief, as needed, and provide information about access to participants.
- Consider shifting the start time or shortening the event if it coincides with the hottest part of the day.
- Encourage attendees to watch out for friends.
- When applicable, enhance medical staffing, crowd monitoring and other health and safety services.
All large and permitted events in New York City must follow on-site medical service mandates, including requirements of permitting agencies and associated contracts.
Heat Index of 100 Degrees F to 104 Degrees F
Follow recommendations from previous heat levels and:
- Consider rescheduling or moving event to an indoor, air-conditioned space.
- Advise participants at higher risk of heat illness of the danger of participation.
- Modify planned activities to minimize physical activity.
- Increase the length of pauses between activities, enabling and encouraging participants to take frequent breaks.
- Discourage participants from trying to record "personal best" times.
- Provide free water and do not provide or sell alcohol.
- If event is not on a natural surface, water down the tarmac/asphalt and monitor the surface temperature with an infrared thermometer. If the temperature reaches 90°F or higher, have plan for additional cooling via high-pressure, high-volume water supply.
Heat Index of 105°F and higher
Reschedule or move event to an indoor, air-conditioned space.