Climateby Month

San Mateo, CA climate by month

NOAA 1991-2020 normals · 45 ft elevation

Highs in San Mateo peak at 75°F in September (mild) and bottom out at 58°F in January (cool). The wettest month is December (about 11 wet days) and the driest is July (about 0). Snow is rare. The most comfortable time to visit is July and August.

Warmest month
75°F
September normal high
Coldest month
45°F
January normal low
Wet days a year
65
19.6 in of precipitation
Muggy days a year
0
dew point 65°F or higher

How warm is San Mateo?

Normal highs range from 58°F in January to 75°F in September.

40°50°60°70°80° January: normal high 58°F (14°C), low 45°F (7°C) 58° 45° February: normal high 61°F (16°C), low 46°F (8°C) March: normal high 63°F (17°C), low 48°F (9°C) April: normal high 66°F (19°C), low 49°F (9°C) May: normal high 68°F (20°C), low 52°F (11°C) June: normal high 72°F (22°C), low 54°F (12°C) July: normal high 73°F (23°C), low 55°F (13°C) August: normal high 73°F (23°C), low 56°F (13°C) September: normal high 75°F (24°C), low 56°F (13°C) 75° 56° October: normal high 72°F (22°C), low 53°F (12°C) November: normal high 64°F (18°C), low 49°F (9°C) December: normal high 58°F (14°C), low 45°F (7°C) JFMAMJJASOND

Bars run from the normal low to the normal high for each month.

How rainy is San Mateo?

December has the most wet days (about 11); the year brings about 20 in of precipitation.

January: 11 wet days February: 11 wet days March: 10 wet days April: 6 wet days May: 3 wet days June: 1 wet days July: 0 wet days 0 August: 0 wet days September: 1 wet days October: 3 wet days November: 7 wet days December: 11 wet days 11 JFMAMJJASOND

Wet day: at least 0.01 in of rain or melted snow, counted from daily records 1991-2020.

How humid is San Mateo?

Muggy days (dew point 65°F or higher) are rare in any month.

January: 0 muggy days 0 February: 0 muggy days March: 0 muggy days April: 0 muggy days May: 0 muggy days June: 0 muggy days July: 0 muggy days August: 0 muggy days September: 0 muggy days October: 0 muggy days November: 0 muggy days December: 0 muggy days JFMAMJJASOND

Muggy day: daily mean dew point of 65°F or higher, from hourly observations 1991-2020 at San Francisco International Airport, 4.5 mi NNW of the city center.

How much daylight?

Daylight ranges from about 9.6 hours in December to 14.7 hours in June.

January: 9.9 hours of daylight February: 10.8 hours of daylight March: 12.0 hours of daylight April: 13.2 hours of daylight May: 14.2 hours of daylight June: 14.7 hours of daylight 14.7 July: 14.5 hours of daylight August: 13.6 hours of daylight September: 12.4 hours of daylight October: 11.2 hours of daylight November: 10.2 hours of daylight December: 9.6 hours of daylight 9.6 JFMAMJJASOND
See all numbers
Monthly climate normals and day counts for San Mateo, 1991-2020
MonthHighLowPrecip.Wet daysMuggy daysDaylight
January 58°F45°F 3.9 in11 0 9.9 h
February 61°F46°F 4.0 in11 0 10.8 h
March 63°F48°F 2.7 in10 0 12.0 h
April 66°F49°F 1.4 in6 0 13.2 h
May 68°F52°F 0.5 in3 0 14.2 h
June 72°F54°F 0.1 in1 0 14.7 h
July 73°F55°F 0.0 in0 0 14.5 h
August 73°F56°F 0.04 in0 0 13.6 h
September 75°F56°F 0.07 in1 0 12.4 h
October 72°F53°F 0.8 in3 0 11.2 h
November 64°F49°F 2.0 in7 0 10.2 h
December 58°F45°F 4.1 in11 0 9.6 h

High and low: NOAA 1991-2020 normal daily high and low. Wet days: at least 0.01 in of rain or melted snow. Muggy days: daily mean dew point 65°F or higher.

Best months to visit San Mateo

By our comfort score, the best months are July and August.

Comfort score by month (0-100) and its parts, in days per month
MonthScoreComfortableNotable rainHot or cold
Jan 44270
Feb 50580
Mar 59960
Apr 681230
May 791820
Jun 892311
Jul 942800
Aug 912701
Sep 832302
Oct 782221
Nov 591140
Dec 43170

Score = 40 × share of comfortable days + 25 × share of days without notable rain + 20 × share of days neither hot (90°F+) nor cold (high 40°F or below) + 15 × daylight. How the score works.

Frost dates in San Mateo

A night at 32°F or below happens in about 12% of years in San Mateo, so there is no typical frost date. In most years there is no frost at all.

Station: San Francisco Intl Airport (USW00023234), NOAA 1991-2020 freeze probabilities. Frost dates for every city in California.

Hottest and coldest readings, 1991-2020

The highest reading was 105°F (June 14, 2000); the lowest was 31°F (December 24, 1998, and 2 other days).

From the temperature station's daily records with NOAA quality flags removed. Not an all-time record.

Near San Mateo

Similar climates elsewhere

Where the numbers come from

  • Temperature, rain, frost dates, humidity and wind by hour and cloud cover: San Francisco Intl Airport (USW00023234), 4.5 mi NNW of the city center, 8 ft . NOAA normals and daily records, 1991-2020.
  • Snowfall and snow depth: Redwood City (USC00047339), 7.6 mi SE of the city center, 31 ft . NOAA normals and daily records, 1991-2020.
  • Daily humidity and wind: San Francisco International Airport (724940-23234), 4.5 mi NNW of the city center, 10 ft . Hourly observations, 1991-2020.

Distances from the city center (USGS). Methodology · Report an error