Walnut Creek, CA climate
Walnut Creek has mild winters and warm summers, with very little rain. A typical July afternoon reaches 87°, a January night drops to 39°, and snow is almost unheard of.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Walnut Creek feels like
Winter
Spring
Summer
Fall
Walnut Creek weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 56° | 39° | 4.2" | 0 | 11 | 0 | 44° – 55° |
| February | 61° | 42° | 3.9" | 0 | 11 | 0 | 45° – 57° |
| March | 65° | 44° | 3.1" | 0 | 11 | 0 | 48° – 61° |
| April | 70° | 46° | 1.4" | 0 | 7 | 0 | 53° – 62° |
| May | 76° | 50° | 0.6" | 0 | 4 | 0 | 56° – 70° |
| June | 83° | 54° | 0.1" | 0 | 1 | 0 | 63° – 72° |
| July | 87° | 57° | 0.0" | 0 | 0 | 0 | 68° – 76° |
| August | 87° | 57° | 0.0" | 0 | 0 | 0 | 68° – 76° |
| September | 84° | 55° | 0.1" | 0 | 1 | 0 | 65° – 74° |
| October | 77° | 50° | 1.0" | 0 | 3 | 0 | 60° – 71° |
| November | 65° | 44° | 2.0" | 0 | 8 | 0 | 47° – 59° |
| December | 56° | 39° | 4.1" | 0 | 12 | 0 | 44° – 51° |
| Year | 72° | 48° | 20.4" | 0.0" | 68 | 0 |
“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 Walnut Creek
Walnut Creek gets 20 inches of rain and melted snow a year. January is the wettest month and July the driest. Rain or snow falls on about 68 days a year.
A year-round growing season
Heating and cooling a home in Walnut Creek
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Walnut Creek, 65% of that work is heating and 35% is cooling.
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.
Walnut Creek and its neighbors
Walnut Creek borders 10 towns with climate data. January nights across them vary by 1.1°. Saranap has the coldest January nights (39°) and Concord the hottest July afternoons (87°). Walnut Creek’s January low is 39° and its July high 87°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Walnut Creek 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 Walnut Creek averaged 1.6° warmer than the 1900s. The biggest change is in January (+2.2°). The shift is larger than in 77% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Walnut Creek’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. May swings the most: between 1991 and 2020 its average temperature ranged from 56° to 70°. December is the most reliable, staying within 7°.
Common questions about Walnut Creek’s climate
What is the coldest month in Walnut Creek?
December, with a typical high of 56° and a low of 39°.
What is the hottest month in Walnut Creek?
July, with a typical high of 87° and a low of 57°. About 47 days a year reach 90°.
How much snow does Walnut Creek get?
Almost none. A normal year brings 0.0 inches.
When is the first frost in Walnut Creek?
Frost is uncommon. Only 80% of years see a night at 32° or below.
What is the rainiest month in Walnut Creek?
January, with 4.2 inches of rain and melted snow. The year totals 20 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Walnut Creek itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Upper San Leandro Filters, CA (11 mi, snow) and Concord WWTP, CA (6 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.