San Ramon, California Weather
Summer heat deepens across the valleys. Day 15 of summer. Read this microseason across nine climate regions →
San Ramon weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJul 5Overcast——74°55°—
- MondayJul 6Foggy——71°51°-3°
- TuesdayJul 7Light Drizzle—0.02″73°52°+2°
- WednesdayJul 8Clear——86°50°+13°
- ThursdayJul 9Partly Cloudy——81°53°-5°
- FridayJul 10Overcast——90°51°+9°
- SaturdayJul 11Overcast——93°54°+3°
AQI 36 (Good), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 8.1 µg/m³, PM10 at 11.3 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 8.1 µg/m³, PM10 at 11.3 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.72
- 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
San Ramon at a glance
- Today vs. normal: 9°F below the seasonal normal for this latitude
- Last frost: April 3 (climatological average for this latitude)
- Microseason: Jul 1–5
- Planting window: Harvest early potatoes. Begin drying onions on the surface.
ZIP codes: 94582, 94583
16-Day Forecast — San Ramon
- Sun74°55°2%
- Mon71°51°1%
- Tue73°52°2%
- Wed86°50°0%
- Thu81°53°0%
- Fri90°51°0%
- Sat93°54°0%
- Sun97°56°1%
- Mon103°65°3%
- Tue98°63°4%
- Wed85°63°0%
- Thu96°66°3%
- Fri104°68°0%
- Sat106°71°3%
- Sun99°61°0%
- Mon89°56°3%
Forecast data from Open-Meteo (CC BY 4.0).
Live wind & temperature near San Ramon
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
San Ramon peaks at about 69°F in July and bottoms near 49°F in January; January brings the heaviest rain (3.4 inches) and July the least (0.0 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 49° | 3.4″ | 13 |
| February | 51° | 3.3″ | 12 |
| March | 53° | 2.7″ | 13 |
| April | 57° | 1.4″ | 9 |
| May | 63° | 0.5″ | 4 |
| June | 67° | 0.0″ | 1 |
| July | 69° | 0.0″ | 1 |
| August | 69° | 0.0″ | 1 |
| September | 69° | 0.1″ | 1 |
| October | 64° | 0.5″ | 4 |
| November | 55° | 2.1″ | 8 |
| December | 49° | 3.0″ | 12 |
Regional context
San Ramon's climate, from NOAA NCEI 1991-2020 station normals, pairs 49°F Januarys with 69°F Julys — a 21°F swing. About 17.2 inches of precipitation falls over roughly 79 days a year.
Cool-season fronts carry San Ramon's rain: January logs 3.4 inches on 13.3 days, against July's 0.0 inches on 0.9 — winter does the heavy lifting in San Ramon. It is a winter-storm rhythm San Ramon shares with places like Norris Canyon, CA, Camino Tassajara, CA and Dublin, CA.
Freezes are uncommon in San Ramon, where the coldest month averages 49°F; cool-season crops grow fall through spring. Summer heat in July (about 69°F) is the binding constraint, not cold. Within San Ramon, low or inland lots lose 3-5°F overnight versus San Ramon's coastal ground.
Similar climates: Norris Canyon, CA, Camino Tassajara, CA, Dublin, CA, Danville, CA, Blackhawk, CA.
Frequently asked
- When does it freeze in San Ramon?
- San Ramon's last spring frost lands near mid-April, and in San Ramon the first fall frost follows around mid-November.
- What is the rainy season in San Ramon?
- Rainfall in San Ramon peaks in January near 3.4 inches, out of about 17 inches annually.
- What is the warmest month in San Ramon?
- San Ramon peaks in July, when the mean runs near 69°F.
- What is the coldest month in San Ramon?
- January is San Ramon's coldest month, averaging about 49°F.
- When can I start a vegetable garden in San Ramon?
- In San Ramon, sow peas and hardy greens around mid-April; San Ramon's tomatoes and peppers wait two weeks more.
- How many rainy days does San Ramon get?
- San Ramon records around 79 days of measurable precipitation annually.
- What hardiness zone is San Ramon?
- With January around 49°F, San Ramon's zone reflects that minimum — the USDA ZIP map confirms San Ramon's band.
- What is the 10-day forecast for San Ramon?
- San Ramon'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 San Ramon?
- See this week's day-by-day rain chances for San Ramon in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in San Ramon?
- Current conditions for San Ramon and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the San Ramon forecast updated?
- The San Ramon forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in San Ramon?
- Today's sunrise and sunset times for San Ramon 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 San Ramon?
- The next few days in San Ramon's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Climate
The hot-summer Mediterranean climate of San Ramon, California carries typical Januarys near 49°F and Julys around 69°F — 20°F of seasonal travel.
In a typical year San Ramon records about 17 inches of precipitation on around 79 days.
San Ramon sits at 37.8°N; that 20°F seasonal swing frames planting windows and frost dates across San Ramon.
ZIP codes in San Ramon
- 94582
- 94583