Rossmoor, California Weather
Summer heat deepens across the valleys. Day 15 of summer. Read this microseason across nine climate regions →
Rossmoor weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJul 5Foggy——81°65°—
- MondayJul 6Overcast——82°61°+1°
- TuesdayJul 7Clear——83°63°+1°
- WednesdayJul 8Clear——86°68°+3°
- ThursdayJul 9Clear——77°69°-9°
- FridayJul 10Overcast——77°68°0°
- SaturdayJul 11Overcast——75°69°-2°
AQI 36 (Good), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 10.3 µg/m³, PM10 at 14.3 µg/m³ — typical background levels with no transport signature.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.
What's driving it
Ozone × UV × Sky
Ozone at AQI 34 now. With UV 12 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 54 around 1 PM.
- Present
- AQI 34
- UV peak
- 12.0 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 54
PM × Wind × Precip
PM2.5 at 10.3 µg/m³, PM10 at 14.3 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.72
- Wind
- light
- Recent rain
- 0h in last 6h
- Pattern
- background
Trends
Seven days of AQI and PM2.5.
Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).








































If the first of July be rainy weather, 'twill rain more or less for four weeks together.
- Moonrise
- 11:08 PM
- Moonset
- 11:11 AM
- In sign
- ♓︎ Pisces
Summer heat deepens across the valleys
Rossmoor at a glance
- Today vs. normal: 77°F — typical for the season
- Last frost: March 10 (climatological average for this latitude)
- Microseason: Jul 1–5
- Planting window: Harvest early potatoes. Begin drying onions on the surface.
16-Day Forecast — Rossmoor
- Sun81°65°0%
- Mon82°61°0%
- Tue83°63°0%
- Wed86°68°0%
- Thu77°69°0%
- Fri77°68°0%
- Sat75°69°1%
- Sun85°69°1%
- Mon88°70°5%
- Tue84°72°8%
- Wed88°72°3%
- Thu92°76°10%
- Fri91°74°11%
- Sat86°73°3%
- Sun87°72°10%
- Mon90°72°11%
Forecast data from Open-Meteo (CC BY 4.0).
Right now in the garden
Peak growing season
As of July 5, the growing season is at its peak — frost is months away. Continue succession-planting beans and summer squash. Start fall brassicas (broccoli, cabbage, kale) from seed indoors for transplanting in late summer.
Microseason · July 1–5
Summer heat deepens across the valleys
Inland temperatures exceed 95°F regularly; fire danger reaches moderate to high across most of the region.
Day 186 of 365 · Wedge 37 of 72
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | — | — |
| February | — | — |
| March | lettuce, peas, spinach, radishes | — |
| April | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | — |
| May | tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| June | tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| July | — | tomatoes, beans, summer squash |
| August | — | tomatoes, beans, summer squash |
| September | — | tomatoes, beans, summer squash |
| October | fall brassicas, garlic (overwinter), carrots | winter squash, tomatoes (last) |
| November | fall brassicas, garlic (overwinter), carrots | — |
| December | — | — |
A year in weather
Rossmoor peaks at about 73°F in August and bottoms near 54°F in January; February brings the heaviest rain (2.5 inches) and August the least (0.0 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 54° | 2.3″ | 9 |
| February | 56° | 2.5″ | 8 |
| March | 58° | 2.0″ | 9 |
| April | 61° | 0.9″ | 7 |
| May | 64° | 0.3″ | 4 |
| June | 68° | 0.0″ | 2 |
| July | 72° | 0.1″ | 1 |
| August | 73° | 0.0″ | 0 |
| September | 72° | 0.0″ | 2 |
| October | 68° | 0.3″ | 3 |
| November | 60° | 1.1″ | 6 |
| December | 54° | 1.8″ | 7 |
Regional context
Per NOAA NCEI 1991-2020 normals, Rossmoor runs from a 54°F January mean to 72°F in July, a 18°F seasonal spread, with near 11.3 inches of precipitation across about 57 wet days.
Cool-season fronts carry Rossmoor's rain: February logs 2.5 inches on 7.6 days, against August's 0.0 inches on 0.2 — winter does the heavy lifting in Rossmoor. That cool-season-wet pattern aligns Rossmoor with places like Los Alamitos, CA, Seal Beach, CA and Hawaiian Gardens, CA.
Hard freezes are rare in Rossmoor: the coldest month averages 54°F, so Rossmoor's growing window runs most of the year. August is the hottest stretch near 73°F, pushing cool-season crops to the milder shoulder months. Across Rossmoor, elevation and tree cover drive a 4-7°F spread in Rossmoor's overnight lows.
Similar climates: Los Alamitos, CA, Seal Beach, CA, Hawaiian Gardens, CA, Cypress, CA, Lakewood, CA.
Frequently asked
- When does it freeze in Rossmoor?
- Rossmoor's last spring frost lands near mid-March, and in Rossmoor the first fall frost follows around mid-December.
- What is the rainy season in Rossmoor?
- February is the wettest month in Rossmoor, about 2.5 inches on average; the year totals roughly 11 inches.
- What is the warmest month in Rossmoor?
- August is Rossmoor's warmest month, averaging about 73°F.
- What is the coldest month in Rossmoor?
- Rossmoor bottoms out in January, with a mean near 54°F.
- When can I start a vegetable garden in Rossmoor?
- Frost-hardy sowings begin at mid-March in Rossmoor; warm-season starts follow two weeks on.
- How many rainy days does Rossmoor get?
- Expect roughly 57 wet days a year in Rossmoor.
- What hardiness zone is Rossmoor?
- Rossmoor sits in the USDA zone set by January lows near 54°F; the USDA ZIP tool gives the band.
- What is the 10-day forecast for Rossmoor?
- Rossmoor's extended outlook — daily high and low temperatures and precipitation chances for each upcoming day — is in the daily forecast above.
- Will it rain this week in Rossmoor?
- See this week's day-by-day rain chances for Rossmoor in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in Rossmoor?
- Current conditions for Rossmoor and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the Rossmoor forecast updated?
- The Rossmoor forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in Rossmoor?
- Today's sunrise and sunset times for Rossmoor are in the Almanac section above, along with civil dawn, civil dusk, and day length. Day length is longest near the summer solstice and shortest near the winter solstice.
- How accurate is the weather forecast for Rossmoor?
- The next few days in Rossmoor's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Climate
Rossmoor, California has a hot-summer Mediterranean climate: January averages roughly 54°F, July about 72°F, 18°F between them.
Across the year, Rossmoor collects about 11 inches of precipitation over roughly 57 days with measurable rain or snow.
Latitude 33.8°N gives Rossmoor its 18°F swing, and with it the rhythm of Rossmoor's growing season.
ZIP codes in Rossmoor
- 90720