The Posey 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
Partly cloudy
Showers likely; cooler
Mostly sunny
Showers likely
Showers likely
Mostly sunny
84° on Nov. 13, 1999, the hottest reading for this week of the year since 1951. Next is 82° in 1990.
Posey’s center stands about 3,640 ft above sea level. Within three miles the land runs from 2,240 ft to 5,320 ft, a difference of 3,080 ft: mountain country. The highest named summit within 15 miles is Sunday Peak, about 8,280 ft, 6 miles east-southeast.
Under the town center the state geologic map shows Mesozoic granitic rocks, unit 3 (Sierra Nevada, Death Valley area, Northern Mojave Desert and Transverse Ranges) (granodiorite), from the Permian to Tertiary, 2.6 to 260 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 3×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Granodiorite. Age: Permian to Tertiary, 2.6 to 260 million years old. About 19 mi of the line.
Schist, gneiss. Age: Paleoproterozoic to Cretaceous, 66 to 2,500 million years old. About 3 mi of the line.
Diorite, gabbro. Age: Triassic to Cretaceous, 66 to 252 million years old. About 2 mi of the line.
Coarse-detrital. Age: Pleistocene, less than 2.6 million years old. About 0.6 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.
A raindrop that lands in Posey reaches the Tulare Lake basin by way of Poso Creek: about 80 river miles. The Tulare Lake basin has no outlet to the sea: the water leaves only by evaporating or soaking into the ground.
Often dry. About 80% of the way is mapped as streams that run only after rain or snowmelt; the water makes the whole trip in floods.
A lake that comes back. The bed of Tulare Lake is farmland now; in very wet years it floods again.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Posey; river miles along the main stem, rounded.
Posey has a warm-summer Mediterranean climate. Summer afternoons average 89° in July; winter nights fall to about 27° in December. A normal year brings about 6 inches of snow; with the rain, that comes to about 19 inches of water.
On November 14 Posey normally reaches 63° and falls to 32°. The record high is 83°, in 1999; the record low 16°, in 1985. The most rain on this date, 1.48 in, fell in 1952.
Normals 1991–2020 and records since 1951 at Glennville, 6 miles south, 500 ft lower. NOAA, through RCC-ACIS.
