Summertime Heat Preparedness Information

Summertime in Iowa means two things:  heat and humidity.  These two weather parameters combine to create the Heat Index (Apparent Temperature), which is an accurate measure of how hot it really feels when relative humidity  is combine with the actual air temperature.   The combination of extreme heat and humidity conspire to tax the human body beyond its natural cooling abilities.  Heat related deaths account for many deaths and injuries each year.  Additional information on Heat Waves as Killers can be found here and here at the main NWS Summertime Preparedness webpage.

Some safety tips during heat waves include:

  • Drink plenty of water or other non-alcohol fluids.
  • Slow down during the heat of the day.
  • Dress in light colored, light weight clothing.
  • Spend more time indoors.
  • Don't get sunburned (Ultra-violet forecasts). 
  • Check frequently on the elderly, youth, and pets during heat waves.


To calculate heat index, you only need two numbers:  the current temperature and current relative humidity.   You can find those by clicking on "Observations" in the left-hand navigational menu, or by clicking here.  Then return to this chart to find the current heat index on the chart below.  Additionally, on the aforementioned observation page, the heat index (if there is one) will be listed on the far right side of each observation in the remarks section.  The Heat Index will be prefaced with "HX".

Heat Index Chart

Graphic depicting heat indices

Main NWS Summer Preparedness Site

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.