Old River, California Weather
Coastal fog thickens at dawn. Day 77 of spring. Read this microseason across nine climate regions →
Old River weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 3Partly Cloudy——96°64°—
- ThursdayJun 4Clear——97°66°+1°
- FridayJun 5Overcast——105°64°+8°
- SaturdayJun 6Overcast——98°72°-7°
- SundayJun 7Clear——94°60°-4°
- MondayJun 8Partly Cloudy——96°57°+2°
- TuesdayJun 9Partly Cloudy——93°60°-3°
Ozone at AQI 71 — peak already passed at 1 PM under clear skies. AQI up 26 in the last 6 hours — air quality is degrading. Levels should ease through evening.
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 71 — peak already passed at 1 PM under clear skies. Levels should ease through evening.
- Present
- AQI 71
- UV peak
- 0.8 at earlier today
- Sky at peak
- clear
- Projected peak
- AQI 71
PM × Wind × Precip
PM2.5 at 13.3 µg/m³, PM10 at 44.8 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.30
- 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).
A summer fog for fair, a winter fog for rain.
- Moonrise
- 6:14 AM
- Moonset
- 4:16 PM
- In sign
- ♑︎ Capricorn
Coastal fog thickens at dawn
Old River at a glance
- Today vs. normal: 13°F above the seasonal normal for this latitude
- Last frost: March 19 (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
Old River's warmest month is July (~84°F mean) and its coldest is December (~48°F). Rainfall peaks in February (1.3 inches) and bottoms out in August (0.0 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 49° | 1.3″ | 4 |
| February | 52° | 1.3″ | 3 |
| March | 57° | 1.2″ | 3 |
| April | 62° | 0.6″ | 2 |
| May | 70° | 0.3″ | 1 |
| June | 77° | 0.0″ | 0 |
| July | 84° | 0.0″ | 0 |
| August | 82° | 0.0″ | 0 |
| September | 77° | 0.1″ | 0 |
| October | 67° | 0.2″ | 1 |
| November | 56° | 0.5″ | 2 |
| December | 48° | 1.0″ | 3 |
Frequently asked
- When does it freeze in Old River?
- Old River's last spring frost typically falls around mid-March, and the first fall frost arrives around mid-December.
- What is the rainy season in Old River?
- February is the wettest month with about 1.3 inches of rain on average; the city receives roughly 7 inches annually.
- What is the warmest month in Old River?
- July is typically warmest, averaging about 84°F.
- What is the coldest month in Old River?
- December is typically coldest, averaging about 48°F.
- When can I start a vegetable garden in Old River?
- 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 Old River get?
- Old River averages about 17 rainy days per year.
- What hardiness zone is Old River?
- Old River'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
Old River, California sits in a hot-summer Mediterranean climate zone. January means hover near 49°F while July averages 84°F — a 35°F seasonal swing.
Across the year, Old River receives about 7 inches of precipitation spread over roughly 17 rainy days.
The rhythm of the year is set by latitude (35.3°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.