The Twin Lakes 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
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Mostly sunny
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89° on Nov. 15, 2008, the hottest reading for this week of the year since 1937. Next is 89° in 2019.
Twin Lakes’s center stands about 50 ft above sea level. Within three miles the land runs from 0 ft to 410 ft, a difference of 410 ft: hilly country. Open water lies within three miles. The highest named summit within 15 miles is Loma Prieta, about 3,780 ft, 13 miles northeast.
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 8×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Sandstone, mudstone. Age: Miocene to Pleistocene, less than 23 million years old. About 8 mi of the line.
Sandstone, mudstone. Age: Oligocene to Pliocene, 2.6 to 34 million years old. About 2 mi of the line.
Coarse-detrital. Age: Pleistocene to Holocene, less than 2.6 million years old. About 1 mi of the line.
Sandstone, mudstone. Age: Eocene to Miocene, 5.3 to 56 million years old. About 0.5 mi of the line.
Mudstone, sandstone. Age: Paleocene to Oligocene, 23 to 66 million years old. About 0.4 mi of the line.
Sandstone, siltstone-mudstone. Age: Late Cretaceous, 66 to 100 million years old. About 0.3 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 Twin Lakes runs straight into the Pacific Ocean.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Twin Lakes; river miles along the main stem, rounded.
Twin Lakes has a warm-summer Mediterranean climate. Summer afternoons average 90° in August; winter nights fall to about 37° in January. About 50 inches of rain fall in a normal year.
On November 14 Twin Lakes normally reaches 72° and falls to 40°. The record high is 88°, in 2021; the record low 27°, in 1985. The most rain on this date, 3.42 in, fell in 1972.
Normals 1991–2020 and records since 1937 at Ben Lomond No. 4, 9 miles north-northwest, 380 ft higher. NOAA, through RCC-ACIS.
