Riverside, WA climate
Riverside has chilly winters and warm summers, with very little rain. A typical July afternoon reaches 89°, a January night drops to 22°.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Riverside feels like
Winter
Spring
Summer
Fall
Riverside weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | 30-yr range |
|---|---|---|---|---|
| January | 34° | 22° | 1.3" | 19° – 33° |
| February | 41° | 24° | 0.8" | 23° – 40° |
| March | 54° | 31° | 1.0" | 37° – 49° |
| April | 64° | 37° | 0.8" | 45° – 57° |
| May | 73° | 45° | 1.2" | 54° – 65° |
| June | 80° | 51° | 1.1" | 61° – 73° |
| July | 89° | 57° | 0.7" | 65° – 78° |
| August | 88° | 57° | 0.4" | 66° – 76° |
| September | 78° | 48° | 0.5" | 59° – 68° |
| October | 62° | 37° | 0.9" | 45° – 55° |
| November | 45° | 29° | 1.3" | 31° – 44° |
| December | 34° | 22° | 1.6" | 22° – 35° |
| Year | 62° | 38° | 11.5" |
“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.
Rain and snow in Riverside
Riverside gets 11 inches of rain and melted snow a year. December is the wettest month and August the driest.
About 160 frost-free days a year
In half of years the last 32° night comes by April 30 and the first one by October 7. That leaves about 160 frost-free days for gardens, shorter than 71% of U.S. towns.
Heating and cooling a home in Riverside
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Riverside, 90% of that work is heating and 10% is cooling, so the furnace matters far more than the air conditioner.
Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.
How Riverside compares
Compared with every U.S. town and city on TownTapestry, each counted once.
Warmer than it used to be
The last 30 years in Riverside averaged 1.1° warmer than the 1900s. The biggest change is in January (+3.8°). The shift is smaller than in 57% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Riverside’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. February swings the most: between 1991 and 2020 its average temperature ranged from 23° to 40°. September is the most reliable, staying within 9°.
Common questions about Riverside’s climate
What is the coldest month in Riverside?
January, with a typical high of 34° and a low of 22°.
What is the hottest month in Riverside?
July, with a typical high of 89° and a low of 57°. About 42 days a year reach 90°.
When is the first frost in Riverside?
In half of years the first 32° night comes by October 7, and the last spring frost by April 30.
What is the rainiest month in Riverside?
December, with 1.6 inches of rain and melted snow. The year totals 11 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Riverside itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Omak Airport, WA (4 mi, frost, heat and degree days). Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.