Weather

The City of Moreno Valley is located in a semi-arid region of western Riverside County just east of the San Bernardino Mountains and south of the San Gabriel Mountains.  The average annual high temperature is 76 degrees with an average low of 49 degrees.  A meager average of close to ten inches of rain falls in any given year.  These conditions make the weather, on average, great for year-round outdoor activity.  Gardening can be done year-round with only minimal threats of a frost in the winter months.

The table below shows the average high and low temperatures and precipitation by months throughout the year.

Winters in the City of Moreno Valley are mild with highs generally in the middle 60s with nights dipping into the upper 30s to lower 40s.  On occasion there can be warm spells with highs jumping into the 70s and even lower 80s, as a warming wind descends the mountains to the north and east.  On the other hand, there also are a few cold spells each winter when high temperatures barely make it to the 50s and nighttime temperatures drop close to the freezing point.  Much of the yearly rainfall in the City of Moreno Valley occurs in the four months from December to March. Nearly 70% of the average annual precipitation occurs in these months.  Despite that, many more days are rain-free in the winter than have rain, with sunshine and clean air allowing great views of the surrounding mountains.  On occasion, from late October through March,  "Santa Ana Winds" visit Moreno Valley and other parts of the Inland Empire.  Santa Ana Winds are gusty, sometimes strong winds that blow from the north and northeast and generally last 12 to 36 hours. This wind event generally occurs between five and ten times a season.

The summers in Moreno Valley generally feature sunny, very warm to hot days and clear, mild nights with an afternoon and evening southwest breeze each day.  The hottest months of July and August have average daily temperatures in the middle 90s with nights in the lower and middle 60s. The naturally occurring low humidity makes these months easier to tolerate than other parts of the nation with similar temperatures.  On occasion from the middle of May through September an unusual hot spell can send afternoon temperatures well over the century mark.  These hot spells typically last only a few days before cooling takes place.   Rainfall in the months from May through September is quite unusual.  On a rare occasion a "Monsoon" pattern develops.  The Monsoon is when moisture moves up from the tropical regions of the Pacific and Gulf of Mexico bringing higher humidity that causes afternoon and evening thunderstorms over the mountains .  Then one or two thunderstorms move out into the Valley from the desert. 

The Spring and Fall months bring the most temperate time of year to the region. It is the season residents look forward to . Many days are still sunny and rain events are uncommon with high temperatures in the 70s and 80s and lows in the 50s .

Also of Interest...

• Moreno Valley Weather Facts in pdf format (13K Acrobat pdf)