Winchester, California Weather
Coastal fog thickens at dawn. Day 77 of spring. Read this microseason across nine climate regions →
Winchester weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 4Clear——89°57°—
- FridayJun 5Mostly Clear——89°56°0°
- SaturdayJun 6Overcast——84°54°-5°
- SundayJun 7Overcast——83°51°-1°
- MondayJun 8Clear——81°49°-2°
- TuesdayJun 9Mostly Clear——77°52°-4°
- WednesdayJun 10Overcast——81°50°+4°
Ozone at AQI 131 now. AQI flat over the last 6 hours (within ±3 points). With UV 9.2 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 161 by mid-afternoon.
CAUTION Sensitive groups (children, elderly, respiratory conditions) should limit prolonged outdoor exertion.
What's driving it
Ozone × UV × Sky
Ozone at AQI 131 now. With UV 9.2 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 161 by mid-afternoon.
- Present
- AQI 131
- UV peak
- 9.2 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 161
PM × Wind × Precip
PM2.5/PM10 ratio 0.69 with 12 mph wind — characteristic of long-range haze transport rather than a local source.
- PM2.5/PM10
- 0.69
- Wind
- breezy
- 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
- 6:01 AM
- Moonset
- 4:12 PM
- In sign
- ♒︎ Aquarius
Coastal fog thickens at dawn
Winchester at a glance
- Today vs. normal: 8°F above 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
Winchester's warmest month is August (~80°F mean) and its coldest is December (~52°F). Rainfall peaks in February (2.8 inches) and bottoms out in June (0.1 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 53° | 2.7″ | 4 |
| February | 54° | 2.8″ | 5 |
| March | 58° | 1.7″ | 4 |
| April | 61° | 0.8″ | 2 |
| May | 67° | 0.5″ | 1 |
| June | 73° | 0.1″ | 0 |
| July | 79° | 0.2″ | 0 |
| August | 80° | 0.1″ | 0 |
| September | 76° | 0.3″ | 1 |
| October | 68° | 0.5″ | 1 |
| November | 59° | 0.8″ | 2 |
| December | 52° | 1.9″ | 3 |
Regional context
Winchester 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 Winchester?
- Winchester's last spring frost typically falls around mid-March, and the first fall frost arrives around mid-December.
- What is the rainy season in Winchester?
- February is the wettest month with about 2.8 inches of rain on average; the city receives roughly 12 inches annually.
- What is the warmest month in Winchester?
- August is typically warmest, averaging about 80°F.
- What is the coldest month in Winchester?
- December is typically coldest, averaging about 52°F.
- When can I start a vegetable garden in Winchester?
- 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 Winchester get?
- Winchester averages about 23 rainy days per year.
- What hardiness zone is Winchester?
- Winchester'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
Winchester, California sits in a hot-summer Mediterranean climate zone. January means hover near 53°F while July averages 79°F — a 26°F seasonal swing.
Across the year, Winchester receives about 12 inches of precipitation spread over roughly 23 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.