Fairfield, California Weather
August begins in scorching stillness. Day 43 of summer. Read this microseason across nine climate regions →
Fairfield weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayAug 2Clear——100°62°—
- MondayAug 3Clear——100°64°0°
- TuesdayAug 4Clear——95°57°-5°
- WednesdayAug 5Clear——95°56°0°
- ThursdayAug 6Clear——98°56°+3°
- FridayAug 7Clear——100°56°+2°
- SaturdayAug 8Clear——101°56°+1°
AQI 50 (Good), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 8.6 µg/m³ (AQI 48) with a 0.88 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 8.6 µg/m³ (AQI 48) with a 0.88 fine-to-coarse ratio and 4 mph wind — combustion smoke trapped in stagnant air, not road dust.
- PM2.5/PM10
- 0.88
- 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
- 9:53 PM
- Moonset
- 10:18 AM
- In sign
- ♓︎ Pisces
August begins in scorching stillness
Fairfield at a glance
- Today vs. normal: 66°F — typical for the season
- Last frost: April 6 (climatological average for this latitude)
- Microseason: Aug 1–5
- Planting window: Sow fall peas. Start kale and collard seedlings for fall.
ZIP codes: 94533, 94534
16-Day Forecast — Fairfield
- Sun100°62°0%
- Mon100°64°0%
- Tue95°57°0%
- Wed95°56°0%
- Thu98°56°0%
- Fri100°56°0%
- Sat101°56°0%
- Sun87°57°0%
- Mon83°57°0%
- Tue82°56°1%
- Wed82°56°0%
- Thu89°56°3%
- Fri89°55°0%
- Sat84°57°0%
- Sun90°56°0%
- Mon100°55°0%
Forecast data from Open-Meteo (CC BY 4.0).
Live wind & temperature near Fairfield
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 Fairfield
Fairfield sits in Solano County, where the year’s longest day runs 14h 50m of daylight and its shortest just 9h 30m — a swing of +5h 20m 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 350 miles to the SE. The nearest town Fairfield tracks is Vallejo, roughly 15 miles to the SW.
Air quality in Fairfield’s county has trended cleaner since 2020; its cleanest year on record was 2025 (median AQI 33). See the full air-quality history for Fairfield.
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 Fairfield, July runs warmest near 74°F and December coldest around 48°F, while December is the wettest month (5.4 inches) and July the driest (0.0 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 49° | 4.7″ | 8 |
| February | 52° | 5.0″ | 8 |
| March | 56° | 3.3″ | 7 |
| April | 60° | 1.5″ | 3 |
| May | 65° | 0.7″ | 2 |
| June | 71° | 0.2″ | 0 |
| July | 74° | 0.0″ | 0 |
| August | 74° | 0.0″ | 0 |
| September | 72° | 0.1″ | 0 |
| October | 65° | 1.1″ | 2 |
| November | 55° | 2.5″ | 5 |
| December | 48° | 5.4″ | 8 |
Regional context
In Fairfield, NOAA NCEI 1991-2020 normals put January near 49°F and July near 74°F — a 25°F seasonal arc — with about 24.5 inches of precipitation over 42 rainy or snowy days.
Fairfield's moisture rides winter storm tracks: December brings 5.4 inches over 7.7 wet days, while July sees only 0.0 inches across 0.0 days in the dry warm season. That cool-season-wet pattern aligns Fairfield with places like Suisun City, CA, Green Valley, CA and Vacaville, CA.
With a coldest-month mean of 48°F, Fairfield stays mostly frost-free and grows year-round. The July peak near 74°F is Fairfield's real limit, pushing cool-season vegetables to spring and fall. Across Fairfield, elevation and tree cover drive a 4-7°F spread in Fairfield's overnight lows.
Similar climates: Suisun City, CA, Green Valley, CA, Vacaville, CA, Elmira, CA, Hartley, CA.
Naturalist notes
Late May brings the distinctive calls of Western Bluebirds as they establish territories in oak woodlands around Fairfield.
California poppies reach peak bloom across the region's grasslands during April and early May.
Frequently asked
- When does it freeze in Fairfield?
- In Fairfield, expect the last spring frost near mid-April; Fairfield's first autumn frost comes around mid-November.
- What is the rainy season in Fairfield?
- December is the wettest month in Fairfield, about 5.4 inches on average; the year totals roughly 25 inches.
- What is the warmest month in Fairfield?
- The warmest stretch in Fairfield comes in July, around 74°F on average.
- What is the coldest month in Fairfield?
- On average December is the chilliest month in Fairfield, about 48°F.
- When can I start a vegetable garden in Fairfield?
- Frost-hardy sowings begin at mid-April in Fairfield; warm-season starts follow two weeks on.
- How many rainy days does Fairfield get?
- Fairfield records around 42 days of measurable precipitation annually.
- What hardiness zone is Fairfield?
- Fairfield sits in the USDA zone set by December lows near 48°F; the USDA ZIP tool gives the band.
- What is the 10-day forecast for Fairfield?
- Fairfield'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 Fairfield?
- See this week's day-by-day rain chances for Fairfield in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in Fairfield?
- Current conditions for Fairfield and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the Fairfield forecast updated?
- The Fairfield forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in Fairfield?
- Today's sunrise and sunset times for Fairfield 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 Fairfield?
- The next few days in Fairfield's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Climate
Fairfield, California occupies a hot-summer Mediterranean zone, with January means near 49°F and July around 74°F — a 25°F swing.
Rain and snow bring Fairfield roughly 25 inches a year across approximately 42 measurable-precipitation days.
Latitude 38.3°N gives Fairfield its 25°F swing, and with it the rhythm of Fairfield's growing season.
ZIP codes in Fairfield
- 94533
- 94534
- 94535