San Jose, California Weather
Coastal fog thickens at dawn. Day 76 of spring. Read this microseason across nine climate regions →
San Jose weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 3Overcast——80°55°—
- ThursdayJun 4Clear——81°51°+1°
- FridayJun 5Clear——92°56°+11°
- SaturdayJun 6Overcast——82°55°-10°
- SundayJun 7Overcast——79°51°-3°
- MondayJun 8Overcast——62°53°-17°
- TuesdayJun 9Overcast——76°58°+14°
PM2.5 at 14.5 µg/m³ (AQI 61) with a 0.72 fine-to-coarse ratio and 3 mph wind — combustion smoke trapped in calm air, not road dust. 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 34 now. With UV 5.8 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 26 by mid-afternoon.
- Present
- AQI 34
- UV peak
- 5.8 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 26
PM × Wind × Precip
PM2.5 at 14.5 µg/m³ (AQI 61) with a 0.72 fine-to-coarse ratio and 3 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.72
- 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).
The higher the clouds, the finer the weather.
- Moonrise
- 5:53 AM
- Moonset
- 3:20 PM
- In sign
- ♑︎ Capricorn
Coastal fog thickens at dawn
San Jose at a glance
- Today vs. normal: 19°F below the seasonal normal for this latitude
- Last frost: March 31 (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 3, 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 | — | — |
| April | lettuce, peas, spinach, radishes | — |
| May | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| June | tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| July | tomatoes, peppers, beans, squash | tomatoes, beans, summer squash |
| August | — | tomatoes, beans, summer squash |
| September | fall brassicas, garlic (overwinter), carrots | tomatoes, beans, summer squash |
| October | fall brassicas, garlic (overwinter), carrots | winter squash, tomatoes (last) |
| November | — | — |
| December | — | — |
A year in weather
August brings San Jose's warmest temperatures (~71°F mean) while December delivers the coldest (~51°F). February sees peak rainfall at 3.2 inches, and July receives 0.0 inches.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 51° | 3.0″ | 7 |
| February | 54° | 3.2″ | 7 |
| March | 57° | 2.6″ | 7 |
| April | 60° | 1.2″ | 3 |
| May | 64° | 0.5″ | 2 |
| June | 69° | 0.2″ | 1 |
| July | 71° | 0.0″ | 0 |
| August | 71° | 0.0″ | 0 |
| September | 70° | 0.1″ | 0 |
| October | 64° | 0.8″ | 2 |
| November | 56° | 1.4″ | 3 |
| December | 51° | 3.1″ | 6 |
Regional context
San Jose falls within a hot-summer Mediterranean climate region — sharing similar temperature ranges, seasonal patterns, and growing conditions with nearby cities.
Similar climates: Los Angeles, CA, San Francisco, CA, San Diego, CA, Riverside, CA, Sacramento, CA.
Naturalist notes
Coast live oaks begin dropping their acorns in late October, carpeting sidewalks and parks throughout San Jose.
Anna's hummingbirds start their breeding season in December, with males performing dramatic dive displays above residential gardens.
Frequently asked
- When does it freeze in San Jose?
- San Jose's last spring frost typically falls around mid-April, and the first fall frost arrives around mid-November.
- What is the rainy season in San Jose?
- February receives the most rain with about 3.2 inches on average; the city gets roughly 16 inches annually.
- What is the warmest month in San Jose?
- August typically brings the warmest weather, averaging about 71°F.
- What is the coldest month in San Jose?
- December typically sees the coldest temperatures, averaging about 51°F.
- When can I start a vegetable garden in San Jose?
- Cool-season crops (peas, lettuce) can be planted around the last spring frost (mid-April); warm-season crops (tomatoes, peppers) should wait until 1–2 weeks after.
- How many rainy days does San Jose get?
- San Jose averages about 38 rainy days per year.
- What hardiness zone is San Jose?
- San Jose's USDA hardiness zone depends on its lowest average winter temperature; check the USDA's online lookup with the city ZIP for the current zone designation.
Climate
San Jose, California experiences a hot-summer Mediterranean climate zone. January temperatures hover near 51°F while July averages 71°F — a 19°F seasonal swing.
Throughout the year, San Jose receives about 16 inches of precipitation spread over roughly 38 rainy days.
Latitude (37.3°N), proximity to large water bodies, and elevation determine the rhythm of the year — shaping what grows here, when frost is likely, and the daily weather patterns.