Clayton, California Weather
Summer heat deepens across the valleys. Day 15 of summer. Read this microseason across nine climate regions →
Clayton weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJul 5Mostly Clear——77°56°—
- MondayJul 6Overcast——74°53°-3°
- TuesdayJul 7Overcast——87°51°+13°
- WednesdayJul 8Clear——94°50°+7°
- ThursdayJul 9Clear——97°54°+3°
- FridayJul 10Overcast——100°54°+3°
- SaturdayJul 11Overcast——102°60°+2°
AQI 30 (Good), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 5.1 µg/m³, PM10 at 6.6 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
PM × Wind × Precip
PM2.5 at 5.1 µg/m³, PM10 at 6.6 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.77
- 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
- 11:27 PM
- Moonset
- 11:26 AM
- In sign
- ♓︎ Pisces
Summer heat deepens across the valleys
Clayton at a glance
- Today vs. normal: 6°F below the seasonal normal for this latitude
- Last frost: April 4 (climatological average for this latitude)
- Microseason: Jul 1–5
- Planting window: Harvest early potatoes. Begin drying onions on the surface.
ZIP code: 94517
16-Day Forecast — Clayton
- Sun77°56°2%
- Mon74°53°1%
- Tue87°51°2%
- Wed94°50°0%
- Thu97°54°0%
- Fri100°54°0%
- Sat102°60°0%
- Sun86°65°1%
- Mon98°66°3%
- Tue103°63°4%
- Wed103°61°1%
- Thu104°60°3%
- Fri107°67°0%
- Sat102°62°3%
- Sun97°58°0%
- Mon98°55°3%
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 | — | — |
| 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
July is Clayton's warmest stretch (~70°F) and January its coldest (~49°F); precipitation crests in January at 3.5 inches and ebbs in July to 0.0 inches.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 49° | 3.5″ | 13 |
| February | 51° | 3.3″ | 12 |
| March | 53° | 2.7″ | 13 |
| April | 58° | 1.4″ | 9 |
| May | 64° | 0.5″ | 4 |
| June | 68° | 0.0″ | 1 |
| July | 70° | 0.0″ | 1 |
| August | 70° | 0.0″ | 1 |
| September | 69° | 0.1″ | 1 |
| October | 64° | 0.6″ | 4 |
| November | 55° | 2.2″ | 8 |
| December | 49° | 3.2″ | 12 |
Regional context
Clayton swings from 49°F in January to 70°F in July (22°F) per NOAA NCEI 1991-2020 normals; precipitation in Clayton runs about 17.5 inches on roughly 79 measurable days.
Precipitation in Clayton peaks in the cool season: January averages 3.5 inches across 13.3 storm-fed days, while July bottoms out at 0.0 inches over just 0.9 rainy days. It is a winter-storm rhythm Clayton shares with places like North Gate, CA, Concord, CA and Pittsburg, CA.
With a coldest-month mean of 49°F, Clayton stays mostly frost-free and grows year-round. The July peak near 70°F is Clayton's real limit, pushing cool-season vegetables to spring and fall. Clayton's coastal lots stay 4-7°F milder overnight than Clayton's inland parcels.
Similar climates: North Gate, CA, Concord, CA, Pittsburg, CA, Shell Ridge, CA, Walnut Creek, CA.
Frequently asked
- When does it freeze in Clayton?
- Frost typically leaves Clayton by mid-April and returns to Clayton near mid-November.
- What is the rainy season in Clayton?
- January is the wettest month in Clayton, about 3.5 inches on average; the year totals roughly 18 inches.
- What is the warmest month in Clayton?
- The warmest stretch in Clayton comes in July, around 70°F on average.
- What is the coldest month in Clayton?
- On average January is the chilliest month in Clayton, about 49°F.
- When can I start a vegetable garden in Clayton?
- Clayton's last frost (mid-April) cues hardy greens; in Clayton, hold heat-lovers two weeks past.
- How many rainy days does Clayton get?
- Clayton records around 79 days of measurable precipitation annually.
- What hardiness zone is Clayton?
- Clayton's USDA zone comes from its January mean (49°F); enter the ZIP on the USDA lookup for the number.
- What is the 10-day forecast for Clayton?
- Clayton'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 Clayton?
- See this week's day-by-day rain chances for Clayton in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in Clayton?
- Current conditions for Clayton and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the Clayton forecast updated?
- The Clayton forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in Clayton?
- Today's sunrise and sunset times for Clayton 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 Clayton?
- The next few days in Clayton's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Climate
Clayton's hot-summer Mediterranean climate in California pairs 49°F Januarys with 70°F Julys, 21°F apart across the seasons.
Rain and snow bring Clayton roughly 18 inches a year across approximately 79 measurable-precipitation days.
The 21°F gap between Clayton's summer and winter, at 37.9°N, shapes Clayton's frost calendar.
ZIP codes in Clayton
- 94517