Fullerton, California Weather
Ceanothus blooms again. Day 93 of summer. Read this microseason across nine climate regions →
Fullerton weather forecast — hour by hour, 7-day outlook, NOAA radar
Conditions updated 1:20 AM PDT · Open-Meteo
- TodaySep 21Overcast——80°65°—
- TuesdaySep 22Mostly Clear——80°62°0°
- WednesdaySep 23Clear——87°69°+7°
- ThursdaySep 24Clear——87°71°0°
- FridaySep 25Overcast——93°72°+6°
- SaturdaySep 26Overcast——94°76°+1°
- SundaySep 27Overcast——94°77°0°
Air quality now AQI 67 · Moderate
AQI 67 (Moderate), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 17.3 µg/m³ (AQI 66) with a 0.86 fine-to-coarse ratio and 3 mph wind — combustion smoke trapped in stagnant 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
PM × Wind × Precip
PM2.5 at 17.3 µg/m³ (AQI 66) with a 0.86 fine-to-coarse ratio and 3 mph wind — combustion smoke trapped in stagnant air, not road dust.
- PM2.5/PM10
- 0.86
- Wind
- calm
- 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).
September dries up ditches or breaks down bridges.
- Moonrise
- 4:10 PM
- Moonset
- 1:36 AM
- In sign
- ♑︎ Capricorn
Ceanothus blooms again
Read this microseason across nine climate regions →
All 72 microseasons on the year wheel →
Fullerton at a glance
- Today vs. normal: Today averages 73°F (high 80°F, low 65°F), about the 74°F normal for Sep 21
- Last frost: None in most years — 32°F in 7% of 1991–2020 years (NOAA station 5 km away)
- Microseason: Sep 21–25
- Planting calendar: September — plant lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash; harvest lettuce, peas, spinach, radishes, tomatoes, peppers, beans, summer squash, winter squash
15-Day Forecast — Fullerton
- Mon80°65°1%
- Tue80°62°0%
- Wed87°69°0%
- Thu87°71°1%
- Fri93°72°0%
- Sat94°76°0%
- Sun94°77°3%
- Mon98°78°6%
- Tue97°85°11%
- Wed93°75°12%
- Thu78°71°3%
- Fri91°73°6%
- Sat93°78°7%
- Sun99°80°5%
- Mon86°80°3%
Forecast data from Open-Meteo (CC BY 4.0).
Live wind & temperature near Fullerton
Interactive wind and temperature map centered on Fullerton — it loads in your browser. Open the full weather map.
Right now in the garden
Year-round growing
As of September 21, sowing here runs through the year. Freezes are uncommon, so there is no frost date to plan around; heat and rainfall set the calendar instead. This city's planting calendar for September: plant lettuce, peas, spinach, radishes, tomatoes, peppers, beans, and squash; harvest lettuce, peas, spinach, radishes, tomatoes, peppers, beans, summer squash, and winter squash.
Sun & seasons in Fullerton
Fullerton sits in Orange County, where the year’s longest day runs 14h 25m of daylight and its shortest just 9h 54m — a swing of +4h 31m between the June and December solstices. Clocks spring forward on Sunday, March 8, 2026 and fall back on Sunday, November 1, 2026.
Los Angeles, the state’s largest city, lies about 32 miles to the WNW. The nearest town Fullerton tracks is Anaheim, roughly 5 miles to the SE.
Air quality in Fullerton
Air quality in Fullerton’s county has held roughly steady since 2020; its cleanest year on record was 2023 (median AQI 52). See the full air-quality history for Fullerton.
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | lettuce, peas, spinach, radishes | lettuce, peas, spinach, radishes |
| February | lettuce, peas, spinach, radishes | lettuce, peas, spinach, radishes |
| March | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, peas, spinach, radishes, tomatoes, peppers, winter squash |
| April | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, peas, spinach, radishes, tomatoes, peppers, summer squash |
| May | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, summer squash |
| June | radishes, tomatoes, peppers, beans, squash | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, summer squash, winter squash |
| July | lettuce, peas, spinach, tomatoes, peppers, beans, squash | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, summer squash, winter squash |
| August | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | tomatoes, peppers, beans, summer squash, winter squash |
| September | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, summer squash, winter squash |
| October | lettuce, peas, spinach, radishes | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, summer squash, winter squash |
| November | lettuce, peas, spinach, radishes, tomatoes, peppers, squash | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, summer squash, winter squash |
| December | lettuce, peas, spinach, radishes | lettuce, peas, spinach, radishes |
A year in weather
The year in Fullerton tops out in August (~77°F) and dips lowest in December (~57°F), with February wettest at 3.0 inches and August driest at 0.0 inches.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 58° | 2.9″ | 5 |
| February | 59° | 3.0″ | 7 |
| March | 61° | 1.7″ | 5 |
| April | 64° | 0.6″ | 4 |
| May | 67° | 0.3″ | 2 |
| June | 71° | 0.1″ | 1 |
| July | 75° | 0.0″ | 0 |
| August | 77° | 0.0″ | 0 |
| September | 75° | 0.1″ | 1 |
| October | 69° | 0.5″ | 3 |
| November | 62° | 0.7″ | 5 |
| December | 57° | 1.9″ | 6 |
Regional context
Similar climates La Habra, CA, Placentia, CA, East Whittier, CA
By the nearest station's NOAA NCEI 1991-2020 normals, Fullerton sees 58°F Januarys and 75°F Julys, an 18°F range, plus around 11.9 inches of precipitation across 38 days.
Precipitation in Fullerton peaks in the cool season: February averages 3.0 inches across 6.8 storm-fed days, while August bottoms out at 0.0 inches over just 0.2 rainy days. It is a winter-storm rhythm Fullerton shares with places like La Habra, CA, Placentia, CA and East Whittier, CA.
Freezes are uncommon in Fullerton, where the coldest month averages 57°F; cool-season crops grow fall through spring. Summer heat in August (about 77°F) is the binding constraint, not cold. Fullerton beds by a wall stay warmer at night.
Similar climates: La Habra, CA, Placentia, CA, East Whittier, CA, Brea, CA, Buena Park, CA.
Frequently asked
- When does it freeze in Fullerton?
- A freeze is the exception in Fullerton: the nearest NOAA station hit 32°F in 7% of 1991–2020 years, too few for a frost date in Fullerton.
- What is the rainy season in Fullerton?
- Fullerton sees its heaviest rain in February (around 3.0 inches), part of roughly 12 inches a year.
- What is the warmest month in Fullerton?
- Fullerton peaks in August, when the mean runs near 77°F.
- What is the coldest month in Fullerton?
- December is Fullerton's coldest month, averaging about 57°F.
- When can I start a vegetable garden in Fullerton?
- Fullerton has no frost date to wait for, so sowing runs year-round; lettuce and greens do best when Fullerton's coldest month settles near 57°F.
- How many rainy days does Fullerton get?
- Fullerton records around 38 days of measurable precipitation annually.
- What hardiness zone is Fullerton?
- With December around 57°F, Fullerton's zone reflects that minimum — the USDA ZIP map confirms Fullerton's band.
- What is the 10-day forecast for Fullerton?
- Fullerton'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 Fullerton?
- See this week's day-by-day rain chances for Fullerton in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in Fullerton?
- Current conditions for Fullerton and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the Fullerton forecast updated?
- The Fullerton forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in Fullerton?
- Today's sunrise and sunset times for Fullerton 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 Fullerton?
- The next few days in Fullerton's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Fullerton sits at 33.9°N; its climate zone is hot-summer Mediterranean (Köppen approximation).
ZIP codes in Fullerton
- 92831
- 92832
- 92833
- 92834
- 92835
- 92836
- 92837
- 92838