Fountain Valley, California Weather
Coastal fog thickens at dawn. Day 77 of spring. Read this microseason across nine climate regions →
Fountain Valley weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 4Foggy——73°63°—
- FridayJun 5Foggy——71°61°-2°
- SaturdayJun 6Foggy——68°60°-3°
- SundayJun 7Overcast——67°63°-1°
- MondayJun 8Mostly Clear——68°63°+1°
- TuesdayJun 9Overcast——67°63°-1°
- WednesdayJun 10Clear——67°61°0°
PM2.5/PM10 ratio 0.63 with 7 mph wind — characteristic of long-range haze transport rather than a local source. AQI flat over the last 6 hours (within ±3 points).
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 55 now. With UV 9.5 peaking around 1 PM under partly cloudy skies, surface ozone likely climbs to AQI 49 by mid-afternoon.
- Present
- AQI 55
- UV peak
- 9.5 at 1 PM
- Sky at peak
- partly cloudy
- Projected peak
- AQI 49
PM × Wind × Precip
PM2.5/PM10 ratio 0.63 with 7 mph wind — characteristic of long-range haze transport rather than a local source.
- PM2.5/PM10
- 0.63
- Wind
- light
- Recent rain
- 0h in last 6h
- Pattern
- transport
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
- 6:04 AM
- Moonset
- 4:16 PM
- In sign
- ♒︎ Aquarius
Coastal fog thickens at dawn
Fountain Valley at a glance
- Today vs. normal: 13°F below the seasonal normal for this latitude
- Last frost: March 9 (climatological average for this latitude)
- Microseason: Jun 1–5
- Planting window: Harvest spring lettuce before it bolts. Sow heat-tolerant greens.
Right now in the garden
Peak growing season
As of June 4, 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.
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
Fountain Valley's warmest month is August (~75°F mean) and its coldest is December (~58°F). Rainfall peaks in February (3.2 inches) and bottoms out in August (0.0 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 59° | 2.9″ | 5 |
| February | 59° | 3.2″ | 5 |
| March | 62° | 1.7″ | 3 |
| April | 64° | 0.8″ | 2 |
| May | 66° | 0.3″ | 1 |
| June | 70° | 0.1″ | 0 |
| July | 74° | 0.0″ | 0 |
| August | 75° | 0.0″ | 0 |
| September | 74° | 0.1″ | 0 |
| October | 69° | 0.5″ | 1 |
| November | 63° | 0.8″ | 2 |
| December | 58° | 2.2″ | 4 |
Regional context
Fountain Valley sits within a hot-summer Mediterranean climate region — a cohort that shares similar temperature ranges, seasonal patterns, and growing conditions across nearby cities.
Similar climates: Los Angeles, CA, San Francisco, CA, San Diego, CA, Riverside, CA, Sacramento, CA.
Frequently asked
- When does it freeze in Fountain Valley?
- Fountain Valley's last spring frost typically falls around mid-March, and the first fall frost arrives around mid-December.
- What is the rainy season in Fountain Valley?
- February is the wettest month with about 3.2 inches of rain on average; the city receives roughly 13 inches annually.
- What is the warmest month in Fountain Valley?
- August is typically warmest, averaging about 75°F.
- What is the coldest month in Fountain Valley?
- December is typically coldest, averaging about 58°F.
- When can I start a vegetable garden in Fountain Valley?
- Cool-season crops (peas, lettuce) can be sown around the last spring frost (mid-March); warm-season crops (tomatoes, peppers) wait until 1–2 weeks after.
- How many rainy days does Fountain Valley get?
- Fountain Valley averages about 22 rainy days per year.
- What hardiness zone is Fountain Valley?
- Fountain Valley's USDA hardiness zone is determined by its lowest average winter temperature; check the USDA's online lookup with the city ZIP for the current zone designation.
Climate
Fountain Valley, California sits in a hot-summer Mediterranean climate zone. January means hover near 59°F while July averages 74°F — a 15°F seasonal swing.
Across the year, Fountain Valley receives about 13 inches of precipitation spread over roughly 22 rainy days.
The rhythm of the year is set by latitude (33.7°N), proximity to large water bodies, and elevation — all of which shape what grows here, when frost is likely, and what the weather story looks like day to day.