Rossmoor sits near the bottom of U.S. towns for precipitation, with 11 inches a year
The depth of winter brings overnight lows near 47°. Temperatures cover 33° across the year, low to high. Summers stay cool: July afternoons here are cooler than in 96% of U.S. towns. Comfortable outdoor weather lasts from January to December, with highs of 67–80°.
A year in Rossmoor at a glance
Each month’s typical high and low, and what it brings.
What stands out about Rossmoor’s climate
Compared with towns across the U.S., with Rossmoor’s place in California beside it.
What a year in Rossmoor feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
Frost is rare
Frost and day counts come from NOAA’s station at Long Beach Daugherty Fld, CA, 4 miles from the town’s center, at about the same height.
The 2023 USDA map puts Rossmoor’s center in zone 10a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 34°. Plant labels use the zone; frost dates tell you when to plant.
90° days by month
Average days at 90° or more
About 11 inches of rain a year
February is the wettest month and August the driest. Rain falls on about 34 days a year. Snow is rare: about 0.0" in a normal year at Torrance Airport, so most winters see none.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Rossmoor
50% of the work is heating. No month averages under 55°.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Long Beach Daugherty Fld, CA.
Living with Rossmoor’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
Zone 10a. Frost comes about 1 winter in 100, so tender plants can often stay out through winter.
Months with highs of 62–84° and lows of 40° or more: January, February, March, April, May, June, July, August, September, October, November and December. 0.3 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Rossmoor from natural hazards, river flooding is the largest share (62%); heat waves, cold waves, winter storms and ice storms together are 1%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Rossmoor and its neighbors
Los Alamitos the hottest July afternoons (81°, 3° warmer). Differences under a degree are within what the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Rossmoor’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Rossmoor, CA | 47° | 78° | 11" | 0.0" |
| Makawao, HI | 53° | 75° | 23" | 0.0" |
| Sequim, WA | 34° | 71° | 18" | 1.4" |
| Winston, OR | 37° | 86° | 33" | 0.0" |
| Alpine, TX | 30° | 90° | 15" | 2.2" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
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°).
A bigger shift than in 97% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Rossmoor compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Rossmoor’s place among California’s.
Rossmoor weather by month
Highs, lows and precipitation from NOAA’s grid at Rossmoor’s center; snow, wet days and snow on the ground from Torrance Airport. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 68° | 47° | 2.7" | 0.0" | 6 | 0 | 54° – 63° |
| February | 67° | 49° | 3.1" | 0.0" | 6 | 0 | 53° – 64° |
| March | 68° | 51° | 1.6" | 0.0" | 5 | 0 | 54° – 67° |
| April | 71° | 53° | 0.6" | 0.0" | 2 | 0 | 58° – 66° |
| May | 72° | 57° | 0.2" | 0.0" | 1 | 0 | 60° – 70° |
| June | 74° | 60° | 0.1" | 0.0" | 1 | 0 | 64° – 71° |
| July | 78° | 64° | 0.0" | 0.0" | 1 | 0 | 67° – 76° |
| August | 80° | 64° | 0.0" | 0.0" | 0 | 0 | 69° – 75° |
| September | 80° | 62° | 0.1" | 0.0" | 0 | 0 | 68° – 76° |
| October | 77° | 59° | 0.4" | 0.0" | 2 | 0 | 64° – 74° |
| November | 73° | 52° | 0.7" | 0.0" | 3 | 0 | 56° – 65° |
| December | 67° | 47° | 1.9" | 0.0" | 6 | 0 | 54° – 61° |
| Year | 73° | 55° | 11.4" | 0.0" | 34 | 0 |
How much a month can swing
A normal is an average. March swings the most: from 1991 to 2020 its average ranged from 54° to 67°. August is the most reliable, staying within 6°.
Where Rossmoor’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Rossmoor’s center.
- Snow: Torrance Airport.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Long Beach Daugherty Fld, CA, 4 miles from the town’s center, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Rossmoor’s climate
What is the weather like in Rossmoor?
A typical July afternoon reaches 78°, a January night drops to 47°, and snow is almost unheard of. Milder January nights than 95% of U.S. towns; cooler July afternoons than 96% of U.S. towns.
How cold does it get in Rossmoor in winter?
December nights average 47°. A night at 32° or below comes in only some winters (0.1 a year on average). In the coldest December of the last 30 years the month averaged 54°.
How much snow does Rossmoor get?
About 0.0 inches in a normal winter at Torrance Airport, so most winters see none.
How hot does it get in Rossmoor?
July, with a typical high of 78° and a low of 64°. About 23 days a year reach 90° and 2 reach 100° (Long Beach Daugherty Fld, CA).
When is the first and last frost in Rossmoor?
Most years have no frost at all: a 32° night comes in about 1% of winters at Long Beach Daugherty Fld, CA, usually in December or January.
What growing zone is Rossmoor in?
Zone 10a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 34°.
What is the best time of year to visit Rossmoor?
By one simple rule (highs of 62–84° and lows of 40° or more), January, February, March, April, May, June, July, August, September, October, November and December. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Rossmoor getting warmer?
Yes: 1991–2020 averaged 2.3° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 97% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Rossmoor.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.