San Mateo, California climate: NOAA's gridded normals for the city, beside the nearest station records
NOAA's gridded 1991-2020 normals put San Mateo's center at January lows of 44°F and July highs of 71°F, a yearly mean of 58.0°F and 20.2 inches of precipitation. No NOAA station keeps a record under the city's name. The nearest station record, Redwood City (7 miles SE, 31 ft), has January lows of 41°F and July highs of 81°F.
103,006 people (Census Bureau 2024). Distances and directions are from the city's center.
- Jan 58° 44°
- Feb 60° 46°
- Mar 63° 48°
- Apr 65° 49°
- May 67° 52°
- Jun 70° 54°
- Jul 71° 56°
- Aug 71° 56°
- Sep 72° 55°
- Oct 70° 53°
- Nov 63° 48°
- Dec 58° 44°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
The months above are NOAA's gridded normals at San Mateo's center.
What is each month like in San Mateo?
NOAA's grid estimates the normals every 5 km or so from the stations around each point, terrain included. It smooths between stations, so night lows at the heart of a large city can run warmer than the grid shows: at five big-city airports we compared, the grid's highs were within about 1°F of the station and its lows 1-6°F cooler. The nearest record's high and low are beside each month.
| Month | High | Low | Mean | Precip. | Redwood City high | Redwood City low |
|---|---|---|---|---|---|---|
| January | 58°F | 44°F | 51.3°F | 4.01 | 59°F | 41°F |
| February | 60°F | 46°F | 53.2°F | 3.91 | 62°F | 43°F |
| March | 63°F | 48°F | 55.1°F | 2.99 | 65°F | 45°F |
| April | 65°F | 49°F | 56.7°F | 1.41 | 69°F | 47°F |
| May | 67°F | 52°F | 59.3°F | 0.64 | 73°F | 50°F |
| June | 70°F | 54°F | 61.8°F | 0.15 | 79°F | 54°F |
| July | 71°F | 56°F | 63.2°F | 0.01 | 81°F | 57°F |
| August | 71°F | 56°F | 63.8°F | 0.04 | 81°F | 57°F |
| September | 72°F | 55°F | 63.8°F | 0.09 | 79°F | 54°F |
| October | 70°F | 53°F | 61.3°F | 0.93 | 75°F | 50°F |
| November | 63°F | 48°F | 55.6°F | 1.95 | 65°F | 44°F |
| December | 58°F | 44°F | 51.2°F | 4.02 | 59°F | 40°F |
In metric: a yearly mean of 14.4°C, January lows of 7°C, July highs of 22°C and 512 mm of precipitation a year.
Source: NOAA NCEI U.S. Monthly Gridded Climate Normals 1991-2020 (nClimGrid, accession 0245564); NOAA NCEI 1991-2020 station normals. The grid cell holding the city's Census center point.
What do the station records around San Mateo say?
Each row is a NOAA station's own 1991-2020 normals, with the snow and frost dates the grid does not give. A record downhill or nearer the coast than the city can run warmer, one uphill cooler: compare the elevations.
| Record | Where | Elevation | Year | Jan low | Jul high | Precip. | Snow | Last frost |
|---|---|---|---|---|---|---|---|---|
| Redwood City | 7 mi SE | 31 ft | 59.4°F | 41°F | 81°F | 19.0 | 0 | January 17 |
| Pacifica4 mi SSE | 9 mi W | 475 ft | 57.4°F | 45°F | 69°F | 31.9 | 0 | January 11 |
| Half Moon Bay | 9 mi SW | 27 ft | 54.9°F | 43°F | 65°F | 26.0 | 0 | February 6 |
Source: NOAA NCEI 1991-2020 U.S. Climate Normals; place center and population: Census Bureau 2024. Last frost: the median last spring date of 32°F.
How much snow, how late a frost, what zone and how much sun in San Mateo?
NOAA's grid gives no snow, frost dates or records, so these come from the nearest station record, Redwood City (7 miles SE, 31 ft). It gets 0 inches of snow in a normal year. The last spring frost (32°F) comes after January 17 in half of years and the first autumn frost before December 12. Its record high is 110°F (1972) and its record low 16°F (1949) (kept since 1930).
The USDA's 2023 Plant Hardiness Zone Map puts San Mateo in zone 10a across its 4 ZIP code areas.
Over a year 80% of the sunlight that would reach the ground under clear skies gets through the clouds in the area (4.7 kWh per square metre a day, NASA POWER 2001-2020); June is the sunniest month (84%) and December the cloudiest (74%).
Redwood City's page has its months, frost probabilities, records by month and recent years. NOAA's grid has monthly figures only, so there are no day-by-day month pages for San Mateo; the nearest record's month pages have them.
Source: NOAA NCEI 1991-2020 normals, station USC00047339; records: ACIS; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; sunshine: NASA POWER.
How does the climate vary across San Mateo, ZIP code by ZIP code?
4 ZIP code areas lie wholly or partly in San Mateo. On NOAA's grid 94404 is the warmest (58.4°F a year) and 94403 the coolest (57.9°F), a spread of 0.5°F. Each row also names the nearest station record and its frost dates.
| ZIP code | Zone | Year | Jan low | Jul high | Precip. | Nearest record | Last frost | First frost |
|---|---|---|---|---|---|---|---|---|
| 94401 | 10a | 58.0°F | 44°F | 71°F | 20.2 | Redwood City (8 mi) | January 17 | December 12 |
| 94402 | 10a | 57.9°F | 42°F | 76°F | 23.5 | Redwood City (7 mi) | January 17 | December 12 |
| 94403 | 10a | 57.9°F | 42°F | 76°F | 23.5 | Redwood City (6 mi) | January 17 | December 12 |
| 94404 | 10a | 58.4°F | 44°F | 72°F | 19.0 | Redwood City (6 mi) | January 17 | December 12 |
Source: Census Bureau 2020 ZCTA-to-place relationship file and ZCTA centers; NOAA NCEI gridded and station normals, 1991-2020. A ZIP area counts when at least a tenth of its land (and 0.5 km²) is in the city; its figures are the grid cell at its center; frost dates are the nearest record's medians of 32°F.