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Summer Dangers: NWS Products

Heat Index
NWS Products
Heat and the Body
Staying Safe


What To Listen For

When extreme heat threatens, look for these products issued by the National Weather Service in Des Moines:

**For detailed information on how to stay safe in the heat, please see our Staying Safe page**

Product What It Means You Should...
Hazardous Weather Outlook Will there be any dangerous heat in the next week?

If any dangerous heat is expected, check back for later forecasts, information and possible advisories, watches or warnings.

Latest Hazardous Weather Outlook
Latest Weather Story Graphic

Heat Advisory Temperatures of at least 100°F* or Heat Index values of at least 105°F* are expected within the next 24 hours, or occasionally further into the future.

Consider postponing or rescheduling any strenuous outdoor activities. If you must be outside, be sure to drink plenty of water and take frequent breaks in the shade. The young and elderly and those with medical conditions should use extra caution outdoors.

Excessive Heat Watch Conditions are favorable for temperatures to reach excessive heat criteria (see below) in the next 12 to 48 hours, or occasionally further into the future.

Plan to suspend all major daytime outdoor activities if a warning is issued. If you do not have air conditioning, locate the nearest cooling shelter or discuss staying with nearby family or friends who have A/C.

Excessive Heat Warning Heat Index values are expected to reach or exceed 110°F* and not fall below 75°F* for at least a 48 hour period beginning in the next 24 hours. A heat warning may be issued for several days during prolonged heat waves.

Refrain from outdoor activities of any nature during the warmest time of the day. Drink plenty of water and take frequent breaks if you must be outside. Stay indoors in an air conditioned building as much as possible. Check on elderly family members if they are living alone.

*The criteria listed above may be deviated from occasionally depending on the impacts to the public. For example: a heat product may be issued for lower temperatures or Heat Index values early in the season. National Weather Service Des Moines meteorologists work closely with public health officials to determine potential impacts to the public from heat.

The criteria for these products vary throughout the United States. In general, the Heat Index and temperature thresholds for each product are lower across the northern portions of the country compared to the southern regions. Please consult your local National Weather Service office for more details. is the U.S. government's official web portal to all federal, state and local government web resources and services.