Antioch, California Weather
Ceanothus blooms again. Day 93 of summer. Read this microseason across nine climate regions →
Antioch weather forecast — hour by hour, 7-day outlook, NOAA radar
Conditions updated 7:24 AM PDT · Open-Meteo
- TodaySep 21Clear——78°56°—
- TuesdaySep 22Clear——81°54°+3°
- WednesdaySep 23Mostly Clear——91°59°+10°
- ThursdaySep 24Overcast——92°62°+1°
- FridaySep 25Overcast——86°60°-6°
- SaturdaySep 26Overcast——87°59°+1°
- SundaySep 27Overcast——81°53°-6°
Air quality now AQI 51 · Moderate
AQI 51 (Moderate), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 8.9 µg/m³ (AQI 49) with a 0.79 fine-to-coarse ratio and 5 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 8.9 µg/m³ (AQI 49) with a 0.79 fine-to-coarse ratio and 5 mph wind — combustion smoke trapped in stagnant air, not road dust.
- PM2.5/PM10
- 0.79
- Wind
- light
- 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).
September dries up ditches or breaks down bridges.
- Moonrise
- 4:37 PM
- Moonset
- 1:40 AM
- In sign
- ♑︎ Capricorn
Ceanothus blooms again
Read this microseason across nine climate regions →
All 72 microseasons on the year wheel →
Antioch at a glance
- Today vs. normal: Today averages 67°F (high 78°F, low 56°F), 4°F below the 71°F normal for Sep 21
- Last frost: January 12 (1991–2020 median, NOAA station 4 km away)
- Microseason: Sep 21–25
- Planting calendar: September — plant tomatoes, peppers, beans, squash; harvest tomatoes, peppers, beans, summer squash, winter squash
16-Day Forecast — Antioch
- Mon78°56°1%
- Tue81°54°1%
- Wed91°59°0%
- Thu92°62°0%
- Fri86°60°0%
- Sat87°59°0%
- Sun81°53°1%
- Mon88°57°1%
- Tue94°63°1%
- Wed96°65°2%
- Thu90°72°0%
- Fri92°76°6%
- Sat101°71°0%
- Sun97°65°0%
- Mon88°58°0%
- Tue87°59°0%
Forecast data from Open-Meteo (CC BY 4.0).
Live wind & temperature near Antioch
Interactive wind and temperature map centered on Antioch — it loads in your browser. Open the full weather map.
Right now in the garden
Peak growing season
As of September 21, the growing season is at its peak — the first frost (around December 19) is weeks away. Fall transplants go in about 10–12 weeks before the first frost, September 26 to October 10 here. This city's planting calendar for September: plant tomatoes, peppers, beans, and squash; harvest tomatoes, peppers, beans, summer squash, and winter squash.
Sun & seasons in Antioch
Antioch sits in Contra Costa County, where the year’s longest day runs 14h 48m of daylight and its shortest just 9h 31m — a swing of +5h 17m 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 327 miles to the SE. The nearest town Antioch tracks is Concord, roughly 11 miles to the W.
Air quality in Antioch
Air quality in Antioch’s county has held roughly steady since 2020; its cleanest year on record was 2021 (median AQI 47). See the full air-quality history for Antioch.
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | lettuce, peas, spinach, radishes | spinach, radishes, fall brassicas, carrots |
| February | — | lettuce, peas, spinach, radishes |
| March | — | lettuce, peas, spinach |
| April | tomatoes, peppers, beans, squash | lettuce, peas |
| May | tomatoes, peppers, beans, squash | garlic |
| June | beans, squash | tomatoes, peppers, beans, summer squash |
| July | beans, squash | tomatoes, peppers, beans, summer squash, winter squash |
| August | tomatoes, peppers, beans, squash | tomatoes, peppers, beans, summer squash, winter squash |
| September | tomatoes, peppers, beans, squash | tomatoes, peppers, beans, summer squash, winter squash |
| October | beans, squash, fall brassicas, carrots | beans, summer squash, winter squash |
| November | garlic (overwinter) | tomatoes, peppers, beans, summer squash, winter squash |
| December | lettuce, peas, spinach, radishes | tomatoes, peppers, beans, summer squash, winter squash, fall brassicas, carrots |
A year in weather
In Antioch, July runs warmest near 76°F and January coldest around 48°F, while January is the wettest month (2.7 inches) and July the driest (0.0 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 48° | 2.7″ | 6 |
| February | 52° | 2.4″ | 6 |
| March | 57° | 1.9″ | 5 |
| April | 61° | 0.9″ | 2 |
| May | 67° | 0.4″ | 1 |
| June | 73° | 0.1″ | 0 |
| July | 76° | 0.0″ | 0 |
| August | 75° | 0.0″ | 0 |
| September | 73° | 0.1″ | 0 |
| October | 66° | 0.4″ | 1 |
| November | 55° | 1.2″ | 3 |
| December | 48° | 2.5″ | 6 |
Regional context
Similar climates Brentwood, CA, Oakley, CA, Pittsburg, CA
In Antioch, NOAA NCEI 1991-2020 normals put January near 48°F and July near 76°F — a 28°F seasonal arc — with about 12.6 inches of precipitation over 30 rainy or snowy days.
Cool-season fronts carry Antioch's rain: January logs 2.7 inches on 6.4 days, against July's 0.0 inches on 0.0 — winter does the heavy lifting in Antioch. That groups Antioch with places like Brentwood, CA, Oakley, CA and Pittsburg, CA on the same cool-season storm track.
Antioch reaches its last hard frost near January 12; that is the cue for lettuce, chard, arugula, and mustard greens. Heat-demanding starts go out a fortnight on in Antioch, after the soil warms and cold snaps clear. The season ends by December 19 in Antioch, once hard frosts set back in. Open lawns in Antioch whiten first when frost returns.
Similar climates: Brentwood, CA, Oakley, CA, Pittsburg, CA, Clayton, CA, Knightsen, CA.
Frequently asked
- When does it freeze in Antioch?
- Antioch's last spring frost lands near January 12, and in Antioch the first fall frost follows around December 19.
- What is the rainy season in Antioch?
- Rainfall in Antioch peaks in January near 2.7 inches, out of about 13 inches annually.
- What is the warmest month in Antioch?
- The warmest stretch in Antioch comes in July, around 76°F on average.
- What is the coldest month in Antioch?
- On average January is the chilliest month in Antioch, about 48°F.
- When can I start a vegetable garden in Antioch?
- Time tomatoes in Antioch for two weeks after January 12; peas and greens start at Antioch's frost line.
- How many rainy days does Antioch get?
- Antioch averages about 30 days with measurable rain or snow each year.
- What hardiness zone is Antioch?
- Antioch's USDA zone comes from its January mean (48°F); enter the ZIP on the USDA lookup for the number.
- What is the 10-day forecast for Antioch?
- Antioch'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 Antioch?
- See this week's day-by-day rain chances for Antioch in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in Antioch?
- Current conditions for Antioch and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the Antioch forecast updated?
- The Antioch forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in Antioch?
- Today's sunrise and sunset times for Antioch 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 Antioch?
- The next few days in Antioch's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Antioch sits at 38.0°N; its climate zone is hot-summer Mediterranean (Köppen approximation).
ZIP codes in Antioch
- 94509
- 94531