Los Altos, CA climate
Los Altos has mild winters and pleasant summers, with very little rain. A typical July afternoon reaches 82°, a January night drops to 40°, and snow is almost unheard of.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Los Altos feels like
Winter
Spring
Summer
Fall
Los Altos 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 | 60° | 40° | 4.4" | 0 | 9 | 0 | 47° – 54° |
| February | 62° | 42° | 4.5" | 0 | 9 | 0 | 48° – 57° |
| March | 66° | 43° | 3.5" | 0 | 9 | 0 | 50° – 59° |
| April | 69° | 45° | 1.6" | 0 | 5 | 0 | 53° – 60° |
| May | 73° | 48° | 0.7" | 0 | 3 | 0 | 57° – 65° |
| June | 79° | 51° | 0.2" | 0 | 1 | 0 | 62° – 68° |
| July | 82° | 54° | 0.0" | 0 | 0 | 0 | 65° – 71° |
| August | 82° | 54° | 0.0" | 0 | 0 | 0 | 66° – 72° |
| September | 81° | 53° | 0.1" | 0 | 1 | 0 | 64° – 71° |
| October | 76° | 49° | 0.9" | 0 | 3 | 0 | 59° – 68° |
| November | 66° | 43° | 2.2" | 0 | 6 | 0 | 48° – 58° |
| December | 59° | 39° | 4.4" | 0 | 9 | 0 | 45° – 54° |
| Year | 71° | 47° | 22.4" | 0.0" | 55 | 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 Los Altos
Los Altos gets 22 inches of rain and melted snow a year. February is the wettest month and July the driest. Rain or snow falls on about 55 days a year.
About 275 frost-free days a year
In half of years the last 32° night comes by March 21 and the first one by December 15. That leaves about 275 frost-free days for gardens, longer than 93% of U.S. towns.
Heating and cooling a home in Los Altos
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Los Altos, 83% of that work is heating and 17% 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.
Los Altos and its neighbors
Los Altos borders 6 towns with climate data. January nights across them vary by 1.8°. Cupertino has both the coldest January nights (39°) and the hottest July afternoons (83°). Los Altos’s January low is 40° and its July high 82°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Los Altos 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 Los Altos averaged 1.9° warmer than the 1900s. The biggest change is in August (+2.2°). The shift is larger than in 90% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Los Altos’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. November swings the most: between 1991 and 2020 its average temperature ranged from 48° to 58°. July is the most reliable, staying within 6°.
Common questions about Los Altos’s climate
What is the coldest month in Los Altos?
December, with a typical high of 59° and a low of 39°.
What is the hottest month in Los Altos?
August, with a typical high of 82° and a low of 54°. About 13 days a year reach 90°.
How much snow does Los Altos get?
Almost none. A normal year brings 0.0 inches.
When is the first frost in Los Altos?
In half of years the first 32° night comes by December 15, and the last spring frost by March 21.
What is the rainiest month in Los Altos?
February, with 4.5 inches of rain and melted snow. The year totals 22 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Los Altos itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Redwood City, CA (11 mi, snow) and Skyline Ridge Preserve, 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.