Weather · September
San Mateo weather in September
Average highs of 75°F, lows of 56°F and 0.10 in of rain, from 30 years of weather records.
September is San Mateo’s warmest month, with average highs of 75°F and lows of 56°F. That is 1° warmer than August, and 8° above the yearly average high.
- Average high
- 75°F
- Average low
- 56°F
- Precipitation
- 0.10 in
- Wet days
- 1
- Sunrise · sunset
- 6:51 AM · 7:18 PM
What to wear in September
- Mild days: dress in layers, with a light jacket or sweater for mornings and evenings.
What September weather is good for
What’s on in San Mateo in September
Guides for this month: Halloween in San Mateo.
See all upcoming events and school days off.
September compared with the months around it
Planning a trip? See the best time to visit San Mateo and today’s forecast.
Questions
How hot does it get in San Mateo in September?
Average highs are 75°F and average lows 56°F, for a daily mean of 65°F. Individual days run hotter or colder than these 30-year averages.
Does it rain in San Mateo in September?
September averages 0.10 in of precipitation over about 1 days with at least 0.01 in. It is the 10th wettest month of the year.
What time is sunset in San Mateo in September?
Around mid-September the sun rises about 6:51 AM and sets about 7:18 PM, for roughly 12.5 hours of daylight.
Is September a good time to visit San Mateo?
The mildest months for visiting are June, July, August. September is mild, with Halloween events.
NOAA U.S. Climate Normals 1991–2020, San Francisco Intl Ap station (5.3 mi from downtown). Sunrise and sunset are calculated for September 15 at the city’s coordinates.