The San Mateo plate. Relief from Copernicus GLO-30; rivers and lakes from USGS NHD; watersheds from the USGS Watershed Boundary Dataset; roads and city limits from Census TIGER 2024.
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79° on Nov. 15, 2008, the hottest reading for this week of the year since 1945. Next is 78° in 2010.
San Mateo’s center stands about 50 ft above sea level. Within three miles the land runs from 0 ft to 640 ft, a difference of 640 ft: hilly country. Open water lies within three miles. The highest named summit within 15 miles is Morena Sierra, about 2,450 ft, 11 miles south.
Under the town center the state geologic map shows Older Quaternary alluvium and marine deposits (coarse-detrital), from the Pleistocene, less than 2.6 million years old.
The section below crosses 6 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 9×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Mudstone, sandstone. Age: Paleocene to Oligocene, 23 to 66 million years old. About 5 mi of the line.
Melange. Age: Jurassic to Cretaceous, 66 to 202 million years old. About 3 mi of the line.
Coarse-detrital. Age: Pleistocene, less than 2.6 million years old. About 3 mi of the line.
Sandstone, mudstone. Age: Oligocene to Pliocene, 2.6 to 34 million years old. About 2 mi of the line.
Sandstone, mudstone. Age: Jurassic to Cretaceous, 66 to 202 million years old. About 0.8 mi of the line.
Coarse-detrital. Age: Pleistocene to Holocene, less than 2.6 million years old. About 0.5 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale.
Heights from Copernicus GLO-90 (a surface model: it includes buildings and tree canopy); summits from USGS GNIS; rivers from USGS NHDPlus HR; rock from the USGS State Geologic Map Compilation.
Rain that falls on San Mateo runs straight into San Francisco Bay and the Pacific Ocean.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of San Mateo; river miles along the main stem, rounded.
San Mateo has a warm-summer Mediterranean climate. Summer afternoons average 75° in September; winter nights fall to about 44° in January. About 20 inches of rain fall in a normal year.
On November 14 San Mateo normally reaches 65° and falls to 49°. The record high is 78°, in 2008; the record low 36°, in 1978. The most rain on this date, 1.04 in, fell in 1968.
Normals 1991–2020 and records since 1945 from the San Francisco Airport Area threaded record (San Francisco International Airport, 4 miles north-northwest). NOAA, through RCC-ACIS.
