Rossmoor, CA climate
Rossmoor has warm winters and pleasant summers, with very little rain. A typical July afternoon reaches 78°, a January night drops to 47°, and snow is almost unheard of.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Rossmoor feels like
Winter
Spring
Summer
Fall
Rossmoor 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 | 68° | 47° | 2.7" | 0 | 6 | 0 | 54° – 63° |
| February | 67° | 49° | 3.1" | 0 | 6 | 0 | 53° – 64° |
| March | 68° | 51° | 1.6" | 0 | 5 | 0 | 54° – 67° |
| April | 71° | 53° | 0.6" | 0 | 2 | 0 | 58° – 66° |
| May | 72° | 57° | 0.2" | 0 | 1 | 0 | 60° – 70° |
| June | 74° | 60° | 0.1" | 0 | 1 | 0 | 64° – 71° |
| July | 78° | 64° | 0.0" | 0 | 1 | 0 | 67° – 76° |
| August | 80° | 64° | 0.0" | 0 | 0 | 0 | 69° – 75° |
| September | 80° | 62° | 0.1" | 0 | 0 | 0 | 68° – 76° |
| October | 77° | 59° | 0.4" | 0 | 2 | 0 | 64° – 74° |
| November | 73° | 52° | 0.7" | 0 | 3 | 0 | 56° – 65° |
| December | 67° | 47° | 1.9" | 0 | 6 | 0 | 54° – 61° |
| Year | 73° | 55° | 11.4" | 0.0" | 34 | 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 Rossmoor
Rossmoor gets 11 inches of rain and melted snow a year. February is the wettest month and August the driest. Rain or snow falls on about 34 days a year.
A year-round growing season
Heating and cooling a home in Rossmoor
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Rossmoor, 50% of that work is heating and 50% 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.
Rossmoor and its neighbors
Rossmoor borders 2 towns with climate data. January nights across them vary by 0.7°. Los Alamitos has both the coldest January nights (47°) and the hottest July afternoons (81°). Rossmoor’s January low is 47° and its July high 78°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Rossmoor 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 Rossmoor averaged 2.3° warmer than the 1900s. The biggest change is in January (+3.2°). The shift is larger than in 99% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Rossmoor’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. March swings the most: between 1991 and 2020 its average temperature ranged from 54° to 67°. August is the most reliable, staying within 6°.
Common questions about Rossmoor’s climate
What is the coldest month in Rossmoor?
December, with a typical high of 67° and a low of 47°.
What is the hottest month in Rossmoor?
August, with a typical high of 80° and a low of 64°. About 23 days a year reach 90°.
How much snow does Rossmoor get?
Almost none. A normal year brings 0.0 inches.
When is the first frost in Rossmoor?
Frost is uncommon. Only 1% of years see a night at 32° or below.
What is the rainiest month in Rossmoor?
February, with 3.1 inches of rain and melted snow. The year totals 11 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Rossmoor itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Torrance Airport, CA (15 mi, snow) and Long Beach Daugherty Fld, CA (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.