San Francisco weather in October
In October, San Francisco has daytime highs averaging 21 °C, nights around 12 °C, with 2.7 wet days, and a sea temperature of 14 °C. Figures are 1991–2020 climate normals.
- 21.2°C Average high
- 12.0°C Average low
- 2.7days Wet days
- 21mm Rainfall
- 13.7°C Sea temperature
- 11h Daylight
Daily temperatures through October
How October develops
Averages for the first, middle and last part of the month, from daily 1991–2020 normals. Chance of rain is the share of years in which that calendar day recorded more than 1 mm.
| Days | Avg high | Avg low | Chance of rain |
|---|---|---|---|
| 1–10 October | 21.9 °C | 12.6 °C | 6 % |
| 11–20 October | 21.7 °C | 12.2 °C | 7 % |
| 21–31 October | 20.2 °C | 11.4 °C | 12 % |
- Average highs fall from 21.9 °C early in October to 20.2 °C by the end of it.
- Rain is most likely over days 21–31 of October (12 % of days) and least likely over days 1–10 (6 %).
What to expect
| Measure | Typical October | Share of the month |
|---|---|---|
| Days above 25 °C | 5.3 of 31 | 17 % |
| Days above 30 °C | 0.7 of 31 | 2 % |
| Days below 0 °C | 0 of 31 | 0 % |
| Days with more than 1 mm rain | 2.7 of 31 | 9 % |
Conditions in October
| Measure | Average |
|---|---|
| Mean temperature | 16 °C |
| Record high (1991–2020) | 34 °C |
| Record low (1991–2020) | 6.7 °C |
| Relative humidity | 74 % |
| Wind speed | 16 km/h |
| Cloud cover | 38 % |
Where San Francisco ranks in October
| Ranking | Position | Value |
|---|---|---|
| Places with the best weather in North America in October | 18th of 50 | 94/100 |
| The driest places in North America in October | 37th of 50 | 21 mm |
October compared with the months around it
| Month | Avg high | Rainfall | Cloud |
|---|---|---|---|
| August | 21.9 °C | 1 mm | 39 % |
| September | 22.7 °C | 2 mm | 33 % |
| October | 21.2 °C | 21 mm | 38 % |
| November | 16.9 °C | 46 mm | 51 % |
| December | 13.8 °C | 90 mm | 58 % |
See all twelve months for San Francisco
- October is the 4th warmest month here.
- It is the 6th driest month of the year.
- It ranks 4th for least cloud cover.
- Days last about 11 hours from sunrise to sunset.
- It rains on 2.7 of 31 days — 9 % of the month.
- Nights are about 9.2 °C cooler than the middle of the day.
- The hottest October day on record since 1991 reached 34 °C, 13 °C above the usual daytime high.
- Beach score: 49 / 100 — see how this is calculated.
QuestionsOctober in San Francisco, answered
How warm is San Francisco in October?
Daily highs average 21 °C and nights fall to about 12 °C, a spread of 9.2 °C between afternoon and dawn. That makes October the 5th warmest month of the year here.
Does it rain much in San Francisco in October?
October averages 21 mm of rain, spread over about 3 of the 31 days — 9 % of the month. Cloud cover averages 38 % of the sky.
Is the sea warm enough to swim in October?
The sea averages 14 °C off San Francisco in October. Most people find water below 20 °C bracing and above 25 °C comfortable for a long swim; this figure is a monthly surface average, so a sheltered bay on a still afternoon can be warmer.
How long are the days in October?
San Francisco averages 11 hours between sunrise and sunset in October. Day length is computed from latitude and date, so it is exact rather than modelled — but it says nothing about how much of that time is sunny.
Data sources and method
- ERA5 / ERA5-Land reanalysis — Copernicus Climate Change Service (C3S), ECMWF. Copernicus Licence
- Open-Meteo — Open-Meteo.com. CC BY 4.0
- NOAA OISST v2.1 — NOAA Physical Sciences Laboratory. Public domain
- GeoNames — GeoNames.org. CC BY 4.0
- Normal period
- 1991–2020
- Dataset version
- era5-1991-2020-scores1.1
- Last processed
Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: daylight hours, beach and comfort scores, monthly rankings, threshold day counts, chance of a wet day by date, ten-day averages within the month. Full formulas are on the methodology page.
Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.