The Yountville 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.
84° on Nov. 15, 2005, the hottest reading for this week of the year since 1893. Next is 82° in 1906.
Yountville’s center stands about 100 ft above sea level. Within three miles the land runs from 60 ft to 1,240 ft, a difference of 1,180 ft: steep hill country. The highest named summit within 15 miles is Mount Vaca, about 2,800 ft, 14 miles east.
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 7 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.
Dacite. Age: Late Miocene to Late Pliocene, 3 to 7 million years old. About 13 mi of the line.
Siltstone-mudstone. Age: Early Cretaceous, 113 to 145 million years old. About 5 mi of the line.
Sandstone, siltstone-mudstone. Age: Late Cretaceous, 66 to 100 million years old. About 2 mi of the line.
Sandstone, conglomerate. Age: Miocene to Pleistocene, less than 23 million years old. About 1 mi of the line.
Coarse-detrital. Age: Pleistocene to Holocene, less than 2.6 million years old. About 1 mi of the line.
Coarse-detrital. Age: Pleistocene, less than 2.6 million years old. About 0.7 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 1 smaller unit 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 Yountville reaches San Francisco Bay and the Pacific Ocean by way of Dry Creek and the Napa: about 25 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Yountville; river miles along the main stem, rounded.
Yountville has a warm-summer Mediterranean climate. Summer afternoons average 86° in July; winter nights fall to about 38° in January. About 28 inches of rain fall in a normal year.
On November 14 Yountville normally reaches 66° and falls to 42°. The record high is 82°, in 2010; the record low 22°, in 1985. The most rain on this date, 2.05 in, fell in 1953.
Normals 1991–2020 and records since 1893 at Sonoma, 9 miles southwest. NOAA, through RCC-ACIS.