The Middletown 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.
Mostly sunny
Showers likely
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Partly cloudy
82° on Nov. 12, 2014, the hottest reading for this week of the year since 1954. Next is 81° in 1995.
Middletown’s center stands about 1,120 ft above sea level. Within three miles the land runs from 1,000 ft to 2,450 ft, a difference of 1,450 ft: steep hill country. The highest named summit within 15 miles is Cobb Mountain, about 4,730 ft, 7 miles west-northwest.
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 10 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 6×. 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, siltstone-mudstone. Age: Late Cretaceous, 66 to 100 million years old. About 6 mi of the line.
Rhyolite, dacite. Age: Late Miocene to Late Pliocene, 3 to 7 million years old. About 4 mi of the line.
Coarse-detrital. Age: Pleistocene to Holocene, less than 2.6 million years old. About 3 mi of the line.
Siltstone-mudstone. Age: Early Cretaceous, 113 to 145 million years old. About 3 mi of the line.
Dacite. Age: Late Miocene to Late Pliocene, 3 to 7 million years old. About 3 mi of the line.
Serpentinite. Age: Middle Jurassic to Late Jurassic, 145 to 175 million years old. About 2 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 4 smaller units along the line are not listed.
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.
A raindrop that lands in Middletown reaches San Francisco Bay and the Pacific Ocean by way of Dry Creek, Putah Creek, South Fork Putah Creek, Prospect Slough, Cache Slough and the Sacramento: about 120 river miles.
Lake on the way: Lake Berryessa.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Middletown; river miles along the main stem, rounded.
Middletown has a hot-summer Mediterranean climate. Summer afternoons average 91° in July; winter nights fall to about 32° in December. About 30 inches of rain fall in a normal year.
On November 14 Middletown normally reaches 64° and falls to 36°. The record high is 81°, in 1995; the record low 23°, in 1978. The most rain on this date, 3.07 in, fell in 1965.
Normals 1991–2020 and records since 1954 at Clearlake 4 SE, 12 miles north-northeast, 230 ft higher. NOAA, through RCC-ACIS.
