San Francisco, California Weather
Ceanothus blooms again. Day 93 of summer. Read this microseason across nine climate regions →
San Francisco weather forecast — hour by hour, 7-day outlook, NOAA radar
Conditions updated 2:21 AM PDT · Open-Meteo
- TodaySep 21Foggy——56°53°—
- TuesdaySep 22Foggy——64°53°+8°
- WednesdaySep 23Overcast——73°56°+9°
- ThursdaySep 24Overcast——67°56°-6°
- FridaySep 25Overcast——66°57°-1°
- SaturdaySep 26Overcast——68°56°+2°
- SundaySep 27Overcast——67°54°-1°
Air quality now AQI 50 · Good
AQI 50 (Good), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 10.0 µg/m³ (AQI 53) with a 0.64 fine-to-coarse ratio and 6 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
Ozone × UV × Sky
Ozone at AQI 33. Overcast through the UV peak window (cloud cover ~100%) — afternoon ozone should stay flat.
- Present
- AQI 33
- UV peak
- 3.3 at 1 PM
- Sky at peak
- overcast
- Projected peak
- AQI 7
PM × Wind × Precip
PM2.5 at 10.0 µg/m³ (AQI 53) with a 0.64 fine-to-coarse ratio and 6 mph wind — combustion smoke trapped in stagnant air, not road dust.
- PM2.5/PM10
- 0.64
- 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
- 4:39 PM
- Moonset
- 1:44 AM
- In sign
- ♑︎ Capricorn
Ceanothus blooms again
Read this microseason across nine climate regions →
All 72 microseasons on the year wheel →
San Francisco at a glance
- Today vs. normal: Today averages 55°F (high 56°F, low 53°F), 8°F below the 63°F normal for Sep 21
- Last frost: None in most years — 32°F in 20% of 1991–2020 years (NOAA station 18 km away)
- Microseason: Sep 21–25
- Planting calendar: September — plant lettuce, peas, spinach, radishes; harvest lettuce, peas, spinach, radishes, tomatoes, peppers, beans, summer squash
15-Day Forecast — San Francisco
- Mon56°53°2%
- Tue64°53°2%
- Wed73°56°0%
- Thu67°56°0%
- Fri66°57°0%
- Sat68°56°0%
- Sun67°54°1%
- Mon79°56°1%
- Tue85°63°2%
- Wed72°59°6%
- Thu69°56°3%
- Fri67°56°6%
- Sat68°55°6%
- Sun78°59°3%
- Mon74°60°3%
Forecast data from Open-Meteo (CC BY 4.0).
Live wind & temperature near San Francisco
Interactive wind and temperature map centered on San Francisco — it loads in your browser. Open the full weather map.
Right now in the garden
Year-round growing
As of September 21, sowing here runs through the year. Freezes are uncommon, so there is no frost date to plan around; heat and rainfall set the calendar instead. This city's planting calendar for September: plant lettuce, peas, spinach, and radishes; harvest lettuce, peas, spinach, radishes, tomatoes, peppers, beans, and summer squash.
Sun & seasons in San Francisco
San Francisco sits in San Francisco County, where the year’s longest day runs 14h 47m of daylight and its shortest just 9h 33m — a swing of +5h 14m 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 338 miles to the SE. The nearest town San Francisco tracks is Oakland, roughly 13 miles to the E.
Air quality in San Francisco
Air quality in San Francisco’s county has trended cleaner since 2020; its cleanest year on record was 2023 (median AQI 32). See the full air-quality history for San Francisco.
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | lettuce, peas, spinach, radishes | lettuce, peas, spinach, radishes |
| February | lettuce, peas, spinach, radishes | lettuce, peas, spinach, radishes |
| March | lettuce, peas, spinach, radishes | lettuce, peas, spinach, radishes |
| April | lettuce, peas, spinach, radishes | lettuce, peas, spinach, radishes |
| May | lettuce, peas, spinach, radishes | lettuce, peas, spinach, radishes |
| June | lettuce, peas, spinach, radishes | lettuce, peas, spinach, radishes |
| July | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, peas, spinach, radishes |
| August | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, peas, spinach, radishes, beans, summer squash |
| September | lettuce, peas, spinach, radishes | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, summer squash |
| October | lettuce, peas, spinach, radishes | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, summer squash, winter squash |
| November | lettuce, peas, spinach, radishes | lettuce, peas, spinach, radishes |
| December | lettuce, peas, spinach, radishes | lettuce, peas, spinach, radishes |
A year in weather
September is San Francisco's warmest stretch (~63°F) and January its coldest (~52°F); precipitation crests in December at 4.8 inches and ebbs in July to 0.0 inches.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 52° | 4.4″ | 8 |
| February | 54° | 4.4″ | 8 |
| March | 56° | 3.1″ | 7 |
| April | 56° | 1.6″ | 4 |
| May | 58° | 0.7″ | 2 |
| June | 60° | 0.2″ | 1 |
| July | 60° | 0.0″ | 0 |
| August | 62° | 0.1″ | 0 |
| September | 63° | 0.1″ | 0 |
| October | 62° | 0.9″ | 2 |
| November | 57° | 2.6″ | 5 |
| December | 53° | 4.8″ | 8 |
Regional context
Similar climates Broadmoor, CA, Daly City, CA, Brisbane, CA
In San Francisco, NOAA NCEI 1991-2020 normals put January near 52°F and July near 60°F — an 8°F seasonal arc — with about 22.9 inches of precipitation over 45 rainy or snowy days.
San Francisco's moisture rides winter storm tracks: December brings 4.8 inches over 8.0 wet days, while July sees only 0.0 inches across 0.0 days in the dry warm season. That cool-season-wet pattern aligns San Francisco with places like Broadmoor, CA, Daly City, CA and Brisbane, CA.
With a coldest-month mean of 52°F, San Francisco stays mostly frost-free and grows year-round. The September peak near 63°F is San Francisco's real limit, pushing cool-season vegetables to spring and fall. San Francisco's rare cold nights chill open ground first.
Similar climates: Broadmoor, CA, Daly City, CA, Brisbane, CA, Colma, CA, South San Francisco, CA.
Frequently asked
- When does it freeze in San Francisco?
- A freeze is the exception in San Francisco: the nearest NOAA station hit 32°F in 20% of 1991–2020 years, too few for a frost date in San Francisco.
- What is the rainy season in San Francisco?
- December is the wettest month in San Francisco, about 4.8 inches on average; the year totals roughly 23 inches.
- What is the warmest month in San Francisco?
- September is San Francisco's warmest month, averaging about 63°F.
- What is the coldest month in San Francisco?
- San Francisco bottoms out in January, with a mean near 52°F.
- When can I start a vegetable garden in San Francisco?
- Any season works in San Francisco: without a reliable freeze, San Francisco's heat, not frost, decides when greens and tomatoes do best.
- How many rainy days does San Francisco get?
- San Francisco records around 45 days of measurable precipitation annually.
- What hardiness zone is San Francisco?
- San Francisco's hardiness zone tracks its winter low; with January near 52°F, check the USDA ZIP map for the exact zone.
- What is the 10-day forecast for San Francisco?
- San Francisco'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 Francisco?
- See this week's day-by-day rain chances for San Francisco in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in San Francisco?
- Current conditions for San Francisco 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 Francisco forecast updated?
- The San Francisco 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 Francisco?
- Today's sunrise and sunset times for San Francisco 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 Francisco?
- The next few days in San Francisco's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
San Francisco sits at 37.8°N; its climate zone is hot-summer Mediterranean (Köppen approximation).
ZIP codes in San Francisco
- 94102
- 94103
- 94104
- 94105
- 94107
- 94108
- 94109
- 94110
- 94111
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