Vallejo, California Weather
August begins in scorching stillness. Day 43 of summer. Read this microseason across nine climate regions →
Vallejo weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayAug 2Overcast——92°57°—
- MondayAug 3Clear——84°57°-8°
- TuesdayAug 4Mostly Clear——82°58°-2°
- WednesdayAug 5Clear——81°60°-1°
- ThursdayAug 6Clear——85°60°+4°
- FridayAug 7Clear——86°60°+1°
- SaturdayAug 8Clear——86°60°0°
AQI 41 (Good), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 6.9 µg/m³ (AQI 38) with a 0.79 fine-to-coarse ratio and 4 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 6.9 µg/m³ (AQI 38) with a 0.79 fine-to-coarse ratio and 4 mph wind — combustion smoke trapped in stagnant air, not road dust.
- PM2.5/PM10
- 0.79
- 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).
Red sky at night, sailor's delight.
- Moonrise
- 9:54 PM
- Moonset
- 10:19 AM
- In sign
- ♓︎ Pisces
August begins in scorching stillness
Vallejo at a glance
- Today vs. normal: 4°F below the seasonal normal for this latitude
- Last frost: April 5 (climatological average for this latitude)
- Microseason: Aug 1–5
- Planting window: Sow fall peas. Start kale and collard seedlings for fall.
ZIP codes: 94589, 94590, 94591, 94592
16-Day Forecast — Vallejo
- Sun92°57°0%
- Mon84°57°0%
- Tue82°58°0%
- Wed81°60°0%
- Thu85°60°0%
- Fri86°60°0%
- Sat86°60°0%
- Sun74°60°0%
- Mon74°59°0%
- Tue73°59°0%
- Wed73°59°1%
- Thu77°59°3%
- Fri77°60°0%
- Sat75°59°0%
- Sun79°59°3%
- Mon83°59°3%
Forecast data from Open-Meteo (CC BY 4.0).
Live wind & temperature near Vallejo
Right now in the garden
Peak growing season
As of August 2, 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.
Sun & seasons in Vallejo
Vallejo sits in Solano County, where the year’s longest day runs 14h 49m of daylight and its shortest just 9h 31m — a swing of +5h 18m 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 349 miles to the SE. The nearest town Vallejo tracks is Fairfield, roughly 15 miles to the NE.
Air quality in Vallejo’s county has trended cleaner since 2020; its cleanest year on record was 2025 (median AQI 33). See the full air-quality history for Vallejo.
Microseason · August 1–5
August begins in scorching stillness
Calm days dominate early August; temperatures peak; the entire ecosystem is in survival mode.
Day 214 of 365 · Wedge 43 of 72
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
In Vallejo, September runs warmest near 71°F and January coldest around 50°F, while December is the wettest month (4.5 inches) and July the driest (0.0 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 50° | 4.5″ | 15 |
| February | 54° | 3.6″ | 12 |
| March | 57° | 3.2″ | 11 |
| April | 60° | 1.4″ | 5 |
| May | 65° | 0.8″ | 3 |
| June | 69° | 0.2″ | 1 |
| July | 71° | 0.0″ | 1 |
| August | 71° | 0.0″ | 1 |
| September | 71° | 0.1″ | 1 |
| October | 66° | 1.0″ | 3 |
| November | 56° | 2.2″ | 7 |
| December | 50° | 4.5″ | 15 |
Regional context
Vallejo's climate, from NOAA NCEI 1991-2020 station normals, pairs 50°F Januarys with 71°F Julys — a 21°F swing. About 21.5 inches of precipitation falls over roughly 75 days a year.
Cool-season fronts carry Vallejo's rain: December logs 4.5 inches on 15.0 days, against July's 0.0 inches on 1.0 — winter does the heavy lifting in Vallejo. That groups Vallejo with places like Crockett, CA, American Canyon, CA and Benicia, CA on the same cool-season storm track.
Vallejo rarely sees a hard freeze — its coldest month sits near 50°F — so planting spans most of the calendar. Heat peaks in September around 71°F, which confines cool-season crops to the shoulders of summer. Across Vallejo, elevation and tree cover drive a 4-7°F spread in Vallejo's overnight lows.
Similar climates: Crockett, CA, American Canyon, CA, Benicia, CA, Rodeo, CA, Port Costa, CA.
Naturalist notes
Oak trees begin dropping their pollen in late April, coating surfaces with yellow dust as the trees complete their spring reproductive cycle.
Anna's hummingbirds start their courtship displays in late February, with males performing dramatic dive displays that produce distinctive whistling sounds.
Frequently asked
- When does it freeze in Vallejo?
- Frost typically leaves Vallejo by mid-April and returns to Vallejo near mid-November.
- What is the rainy season in Vallejo?
- December is the wettest month in Vallejo, about 4.5 inches on average; the year totals roughly 21 inches.
- What is the warmest month in Vallejo?
- Vallejo peaks in September, when the mean runs near 71°F.
- What is the coldest month in Vallejo?
- January is Vallejo's coldest month, averaging about 50°F.
- When can I start a vegetable garden in Vallejo?
- Around mid-April, start frost-hardy crops in Vallejo; tomatoes and basil belong a fortnight later.
- How many rainy days does Vallejo get?
- Vallejo averages about 75 days with measurable rain or snow each year.
- What hardiness zone is Vallejo?
- With January around 50°F, Vallejo's zone reflects that minimum — the USDA ZIP map confirms Vallejo's band.
- What is the 10-day forecast for Vallejo?
- Vallejo'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 Vallejo?
- See this week's day-by-day rain chances for Vallejo in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in Vallejo?
- Current conditions for Vallejo and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the Vallejo forecast updated?
- The Vallejo forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in Vallejo?
- Today's sunrise and sunset times for Vallejo 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 Vallejo?
- The next few days in Vallejo's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Climate
The hot-summer Mediterranean climate of Vallejo, California carries typical Januarys near 50°F and Julys around 71°F — 21°F of seasonal travel.
In a typical year Vallejo records about 21 inches of precipitation on around 75 days.
Vallejo sits at 38.1°N; that 21°F seasonal swing frames planting windows and frost dates across Vallejo.
ZIP codes in Vallejo
- 94592
- 94591
- 94589
- 94590