30-year climate normals

Riverside County Climate and Weather Averages

Hottest month — July

106.9°

average daily high. The coldest month is December, averaging a low of 37.7°F.

Riverside County gets 2.96" of precipitation a year, and 54% of it falls in Jan, Feb, Mar.

Temperature through the year

Each bar spans the average daily low to the average daily high for that month.

Month	Avg high	Avg low	Precip
January	71.0°	39.0°	0.64"
February	74.3°	42.9°	0.61"
March	81.1°	49.0°	0.34"
April	87.2°	54.8°	0.08"
May	94.6°	62.9°	0.01"
June	103.0°	69.1°	0.01"
July	106.9°	75.6°	0.13"
August	106.2°	74.9°	0.12"
September	101.5°	68.2°	0.32"
October	90.9°	56.9°	0.19"
November	78.7°	44.7°	0.17"
December	69.3°	37.7°	0.34"

Rainfall by month

Riverside County has a distinct wet season. 54% of the year's precipitation arrives in Jan, Feb, Mar.

January 0.64"

February 0.61"

March 0.34"

April 0.08"

May 0.01"

June 0.01"

July 0.13"

August 0.12"

September 0.32"

October 0.19"

November 0.17"

December 0.34"

Annual total 2.96"

What this climate costs you

Degree days measure how hard a building has to work to stay comfortable. They are the reason two identical houses have very different power bills, and they are the link between the weather here and what you pay every month.

Cooling degree days How much air conditioning the climate demands 3,880

Heating degree days How much heating the climate demands 1,108

Approximate annual cooling cost At 33.25¢/kWh, California average $1,290

Approximate annual electric heating cost Lower where heating is gas rather than electric $129

These are rough planning figures from degree days and the state electricity price, not a bill estimate. House size, insulation and fuel type move them a lot. See the full cost of owning a home in Riverside County, where electricity is one line of eight.

Common questions

What is the weather like in Riverside County?

Riverside County averages a high of 106.9°F in July and a low of 37.7°F in December. Annual precipitation is 2.96 inches, with essentially no snow.

When is the rainy season in Riverside County?

The wettest stretch is Jan, Feb, Mar, which accounts for 54% of the year's precipitation. That is a pronounced wet season rather than rain spread evenly through the year.

How hot does it get in Riverside County?

The average daily high in July, the hottest month, is 106.9°F. That drives 3,880 cooling degree days a year, which is what your air conditioning has to work against.

Does it snow in Riverside County?

Effectively no. Measurable snowfall is rare in Riverside County.

Sources

Temperature, precipitation and snowfall normals — NOAA National Centers for Environmental Information, 1991–2020 Monthly Climate Normals, station DESERT RESORTS RGNL AP, CA US (USW00003104), 11.5 miles from the county centroid.
Heating and cooling degree days — NOAA, same station and period.
Electricity price — US Energy Information Administration, Electric Power Monthly Table 5.6.A, California residential average.
Wet-season share is the wettest three consecutive months as a percentage of annual precipitation, calculated from the monthly normals.