The Millbrae 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.
Partly cloudy
Showers likely
Showers likely
Showers likely
Showers likely
Showers likely
Partly cloudy
79° on Nov. 15, 2008, the hottest reading for this week of the year since 1945. Next is 78° in 2010.
Millbrae’s center stands about 30 ft above sea level. Within three miles the land runs from 0 ft to 1,120 ft, a difference of 1,120 ft: steep hill country. Open water lies within three miles. The highest named summit within 15 miles is Morena Sierra, about 2,450 ft, 14 miles south-southeast.
Under the town center the state geologic map shows Quaternary alluvium and marine deposits (coarse-detrital), from the Pleistocene to Holocene, less than 2.6 million years old.
The section below crosses 4 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 36×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Coarse-detrital. Age: Pleistocene to Holocene, less than 2.6 million years old. About 7 mi of the line.
Coarse-detrital. Age: Pleistocene, less than 2.6 million years old. About 6 mi of the line.
Sandstone, mudstone. Age: Miocene to Pleistocene, less than 23 million years old. About 4 mi of the line.
Sandstone, mudstone. Age: Jurassic to Cretaceous, 66 to 202 million years old. About 3 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 Millbrae 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 Millbrae; river miles along the main stem, rounded.
Millbrae 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 Millbrae 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, here). NOAA, through RCC-ACIS.
