Fairfax, California Weather
Summer heat deepens across the valleys. Day 15 of summer. Read this microseason across nine climate regions →
Fairfax weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJul 5Overcast——99°74°—
- MondayJul 6Clear——99°72°0°
- TuesdayJul 7Clear——103°62°+4°
- WednesdayJul 8Clear——104°61°+1°
- ThursdayJul 9Clear——108°62°+4°
- FridayJul 10Clear——110°65°+2°
- SaturdayJul 11Partly Cloudy——112°68°+2°
AQI 59 (Moderate), driven by PM2.5. AQI up 5 over the last 6 hours (gradual rise). PM2.5 at 17.7 µg/m³, PM10 at 59.8 µg/m³ — typical background levels with no transport signature.
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 42 now. With UV 9.3 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 52 around 1 PM.
- Present
- AQI 42
- UV peak
- 9.3 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 52
PM × Wind × Precip
PM2.5 at 17.7 µg/m³, PM10 at 59.8 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).








































If the first of July be rainy weather, 'twill rain more or less for four weeks together.
- Moonrise
- 11:13 PM
- Moonset
- 11:14 AM
- In sign
- ♓︎ Pisces
Summer heat deepens across the valleys
Fairfax at a glance
- Today vs. normal: 12°F above the seasonal normal for this latitude
- Last frost: March 19 (climatological average for this latitude)
- Microseason: Jul 1–5
- Planting window: Harvest early potatoes. Begin drying onions on the surface.
ZIP code: 94930
16-Day Forecast — Fairfax
- Sun99°74°1%
- Mon99°72°0%
- Tue103°62°0%
- Wed104°61°0%
- Thu108°62°0%
- Fri110°65°0%
- Sat112°68°1%
- Sun112°73°2%
- Mon115°73°6%
- Tue114°81°7%
- Wed106°83°3%
- Thu107°78°6%
- Fri113°73°6%
- Sat121°76°10%
- Sun121°81°6%
- Mon115°79°6%
Forecast data from Open-Meteo (CC BY 4.0).
Right now in the garden
Peak growing season
As of July 5, 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.
Microseason · July 1–5
Summer heat deepens across the valleys
Inland temperatures exceed 95°F regularly; fire danger reaches moderate to high across most of the region.
Day 186 of 365 · Wedge 37 of 72
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
Fairfax peaks at about 84°F in July and bottoms near 48°F in December; February brings the heaviest rain (2.0 inches) and August the least (0.0 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 48° | 1.9″ | 13 |
| February | 51° | 2.0″ | 11 |
| March | 54° | 2.0″ | 12 |
| April | 61° | 0.9″ | 8 |
| May | 69° | 0.3″ | 3 |
| June | 76° | 0.0″ | 0 |
| July | 84° | 0.0″ | 1 |
| August | 83° | 0.0″ | 1 |
| September | 76° | 0.1″ | 1 |
| October | 66° | 0.3″ | 2 |
| November | 54° | 1.1″ | 8 |
| December | 48° | 1.7″ | 11 |
Frequently asked
- When does it freeze in Fairfax?
- Fairfax's last spring frost lands near mid-March, and in Fairfax the first fall frost follows around mid-December.
- What is the rainy season in Fairfax?
- Rainfall in Fairfax peaks in February near 2.0 inches, out of about 10 inches annually.
- What is the warmest month in Fairfax?
- On average July tops the year in Fairfax at about 84°F.
- What is the coldest month in Fairfax?
- The coldest stretch in Fairfax falls in December, around 48°F on average.
- When can I start a vegetable garden in Fairfax?
- In Fairfax, sow peas and hardy greens around mid-March; Fairfax's tomatoes and peppers wait two weeks more.
- How many rainy days does Fairfax get?
- Fairfax records around 70 days of measurable precipitation annually.
- What hardiness zone is Fairfax?
- With December around 48°F, Fairfax's zone reflects that minimum — the USDA ZIP map confirms Fairfax's band.
- What is the 10-day forecast for Fairfax?
- Fairfax'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 Fairfax?
- See this week's day-by-day rain chances for Fairfax in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in Fairfax?
- Current conditions for Fairfax and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the Fairfax forecast updated?
- The Fairfax forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in Fairfax?
- Today's sunrise and sunset times for Fairfax 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 Fairfax?
- The next few days in Fairfax's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Climate
In Fairfax, California, the hot-summer Mediterranean climate runs from about 48°F in January to 84°F in July, a 36°F seasonal range.
Fairfax sees close to 10 inches of precipitation annually, falling across some 70 wet days.
Fairfax's 36°F range, set by its 35.3°N position, drives frost timing and what thrives in Fairfax.
ZIP codes in Fairfax
- 93307