Table 1.

Heat index chart

Category	Heat index	Possible heat disorders for people in high risk groups
Extreme danger	130°F or higher (54°C or higher)	Heat stroke or sunstroke likely
Danger	105–129°F (41–54°C)	Sunstroke, muscle cramps, and/or heat exhaustion likely Heatstroke possible with prolonged exposure and/or physical activity
Extreme caution	90–105°F (32–41°C)	Sunstroke, muscle cramps, and/or heat exhaustion possible with prolonged exposure and/or physical activity
Caution	80–90°F (27–32°C)	Fatigue possible with prolonged exposure and/or physical activity

Source: National Oceanic and Atmospheric Administration's National Weather Service (NOAA's NWS), U.S. Department of Commerce, 2009.