Hot, Humid Weather in California

The information here tells how often heat combines with humidity in California cities to create uncomfortably muggy 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 often is the case for hot weather in California.

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.