Rossmoor, California Weather
Bay laurel fragrance sweetens shade. Day 90 of spring. Read this microseason across nine climate regions →
Rossmoor weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 17Foggy——72°64°—
- ThursdayJun 18Light Drizzle—0.03″71°63°-1°
- FridayJun 19Overcast——73°62°+2°
- SaturdayJun 20Mostly Clear——71°63°-2°
- SundayJun 21Mostly Clear——70°63°-1°
- MondayJun 22Mostly Clear——72°64°+2°
- TuesdayJun 23Clear——81°65°+9°
AQI 36 (Good), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 12.0 µg/m³ (AQI 56) with a 0.69 fine-to-coarse ratio and 5 mph wind — combustion smoke trapped in calm air, not road dust.
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 38 now. With UV 8.2 peaking around 1 PM under partly cloudy skies, surface ozone likely climbs to AQI 29 around 1 PM.
- Present
- AQI 38
- UV peak
- 8.2 at 1 PM
- Sky at peak
- partly cloudy
- Projected peak
- AQI 29
PM × Wind × Precip
PM2.5 at 12.0 µg/m³ (AQI 56) with a 0.69 fine-to-coarse ratio and 5 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.69
- Wind
- light
- Recent rain
- 0h in last 6h
- Pattern
- stagnant smoke
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).








































A summer fog for fair, a winter fog for rain.
- Moonrise
- 8:17 AM
- Moonset
- 10:13 PM
- In sign
- ♌︎ Leo
Bay laurel fragrance sweetens shade
Rossmoor at a glance
- Today vs. normal: 16°F below the seasonal normal for this latitude
- Last frost: March 10 (climatological average for this latitude)
- Microseason: Jun 16–20
- Planting window: Stake and prune tomato suckers. Watch for squash vine borers.
16-Day Forecast — Rossmoor
- Wed72°64°0%
- Thu71°63°3%
- Fri73°62°1%
- Sat71°63°0%
- Sun70°63°0%
- Mon72°64°0%
- Tue81°65°0%
- Wed84°67°0%
- Thu80°67°1%
- Fri75°66°0%
- Sat74°67°0%
- Sun72°66°0%
- Mon80°65°0%
- Tue84°67°0%
- Wed76°67°3%
- Thu77°68°3%
Forecast data from Open-Meteo (CC BY 4.0).
Right now in the garden
Peak growing season
As of June 17, 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 · June 16–20
Bay laurel fragrance sweetens shade
In cooler coastal canyons, bay laurel foliage releases its sharp, anise-like scent as temperatures climb.
Day 168 of 365 · Wedge 34 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?
- Day length in Rossmoor peaks around the June solstice — earliest sunrise and latest sunset — and is shortest near the December 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