Climate averages 1991–2020
San Mateo weather
in October.
A mild, fairly dry month: the 5th warmest and the 6th driest of the year. Meets the pleasant-weather rule
Long-term climate patterns, not a forecast for a particular trip.
October is a mild month in San Mateo: daytime highs average 21.7°C and nights cool to about 12.9°C. By daytime temperature it is the 5th warmest of the 12 months.
Expect about 23 mm of rain on roughly 3 days, which makes October a fairly dry month (the 6th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 11 h 15 min on an average October day.
The nearest other city in this atlas is Redwood City (12 km away). In October its highs average 22.1°C, about as warm as San Mateo, with 23 mm of rain.
Among the 498 cities listed in the United States, San Mateo ranks joint 251st of 498 for the warmest October highs and joint 104th of 498 for the driest October (rainfall, lowest first). The mean October high of those 498 cities is 21.4°C; San Mateo is 0.4°C warmer than that mean.
From October to November, average highs fall by 4.7°C to 17.0°C, and monthly rainfall rises from 23 mm to 51 mm.
The annual picture
October in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
San Mateo climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 13.9°C6.7°C | 6.7°C | 99 | 9.4 | 9.910 h |
| February | 14.8°C7.5°C | 7.5°C | 107 | 9.5 | 10.811 h |
| March | 16.1°C8.5°C | 8.5°C | 82 | 9.1 | 11.912 h |
| April | 17.4°C9.3°C | 9.3°C | 41 | 5.6 | 13.113 h |
| May | 19.3°C10.9°C | 10.9°C | 20 | 3.3 | 14.214 h |
| June | 21.8°C12.4°C | 12.4°C | 3.9 | 0.9 | 14.715 h |
| July | 23.2°C13.7°C | 13.7°C | 0.5 | 0.2 | 14.514 h |
| August | 23.6°C14.2°C | 14.2°C | 0.7 | 0.1 | 13.614 h |
| September | 24.0°C14.2°C | 14.2°C | 1.8 | 0.4 | 12.512 h |
| October, selected | 21.7°C12.9°C | 12.9°C | 23 | 3.0 | 11.311 h |
| November | 17.0°C9.9°C | 9.9°C | 51 | 6.0 | 10.210 h |
| December | 13.7°C7.2°C | 7.2°C | 94 | 9.3 | 9.610 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
October in nearby cities
- Redwood City in OctoberUnited States · 12 kmHigh 22.1°C · Low 13.1°C · 23 mm rain
- Daly City in OctoberUnited States · 20 kmHigh 18.8°C · Low 11.5°C · 24 mm rain
- Hayward in OctoberUnited States · 25 kmHigh 23.2°C · Low 12.5°C · 21 mm rain
- San Francisco in OctoberUnited States · 25 kmHigh 21.0°C · Low 11.8°C · 24 mm rain
- Union City in OctoberUnited States · 27 kmHigh 23.7°C · Low 13.1°C · 23 mm rain
- Oakland in OctoberUnited States · 27 kmHigh 23.2°C · Low 12.1°C · 21 mm rain
- Mountain View in OctoberUnited States · 29 kmHigh 23.0°C · Low 13.3°C · 23 mm rain
- Fremont in OctoberUnited States · 30 kmHigh 23.5°C · Low 13.4°C · 23 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for San Mateo) is explained once on the San Mateo year overview and on the Sources, method and limits page.
Redwood City lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.