Hot, Humid Weather in Arizona

The information here tells how often heat and humidity in Arizona cities create uncomfortably hot weather.

The apparent temperature, also known as the Heat Index, measures how hot the weather really feels, considering both temperature and humidity. For instance, a temperature of 90 degrees Fahrenheit (32.2 ° Celsius) along with 60 % humidity pushes the apparent temperature to 100 °F (37.8 °C).

At low levels of humidity, high temperatures seem cooler than what the thermometer reads. This is more often the case for hot weather in Arizona.

These tables list the number of days when the actual temperature and the apparent temperature rose to least 95, 105 or 115 °F (35, 40.6 or 46.1 °C) for an hour or more. The totals are for the 30 years from 1978 to 2007.

The final table breaks the totals into yearly averages for the days when apparent temperatures reach 95 and 105 °F.

Total days with the temperature at least 95 °F
City Actual Apparent
Phoenix 4299 3370
Tucson 3185 1985
Total days with the temperature at least 105 °F
City Actual Apparent
Phoenix 1835 1060
Tucson 496 23
Total days with the temperature at least 115 °F
City Actual Apparent
Phoenix 14 12
Tucson 0 0
Average days a year of apparent temperature
City 95+ °F 105+ °F
Phoenix 112 35
Tucson 66 1

Peter Browning and Brian Walawender. 2009. A Climatology of Apparent Temperature. 21st Conference on Climate Variability and Change.

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