Note: Weather data is provided as a general guide only. Arizona State Parks assumes no responsibility for any loss resulting from use of this information.

Yuma is known as one of the sunniest locations in the United States. Our average annual rainfall is about 3 inches a year, making rain very unlikely to fall on any given day. So unlikely in fact that in Yuma’s early days one of the finest Hotels The Pilot Knob Hotel boasted a free room for every day the sun didn’t shine.

November through March are the most popular months to visit the park, with temperatures ranging from the 60s through the 80s. Springtime often brings windy conditions, although wind and sand storms can occur throughout the year. If the Yuma area receives substantial winter and/or spring rains, there is a good chance to see some Arizona wildflowers at the park. Common wildflowers include Spanish needles, brown-eyed primrose, and the desert marigold.

From April through October, Yuma temperatures climb into the 90s and 100s. April and May are the best months to view our prickly pear and saguaro cacti in bloom. June, July, and August tend to be the hottest months, with temperatures regularly reaching above 110. In July and August, Yuma enters into our monsoon season, which brings higher humidity—though little to no rain. After temperatures peak in July and August, they begin to drop back into the 90s and 80s during September and October.

Below is a listing of average daily temperatures and monthly precipitation:

Yuma Territorial Prison State Historic Park Average Daily Temperature (Degrees Fahrenheit) & monthly Precipitation (Inches)
Month High Low Precipitation
January 70° F 46° F 0.38"
February 75° 49° 0.28"
March 80° 53° 0.27"
April 87° 58° 0.09"
May 95° 65° 0.25"
June 104° 73° 0.02"
July 107° 81° 0.23"
August 106° 81° 0.61"
September 101° 75° 0.26"
October 90° 64° 0.26"
November 77° 52° 0.14"
December 69° 46° 0.42"

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