The Porterville 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
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Chance of showers; cooler
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Mostly sunny
88° on Nov. 12, 2016, the hottest reading for this week of the year since 1913. Next is 84° in 1953.
Porterville’s center stands about 460 ft above sea level. Within three miles the land runs from 420 ft to 1,210 ft, a difference of 790 ft: hilly country. The highest named summit within 15 miles is Cow Mountain, about 3,720 ft, 13 miles east.
Under the town center the state geologic map shows Older Quaternary alluvium and marine deposits (coarse-detrital), from the Pleistocene, less than 2.6 million years old.
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 9×. 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, less than 2.6 million years old. About 12 mi of the line.
Granodiorite. Age: Permian to Tertiary, 2.6 to 260 million years old. About 7 mi of the line.
Coarse-detrital. Age: Pleistocene to Holocene, less than 2.6 million years old. About 4 mi of the line.
Basalt, serpentinite. Age: Ordovician to Permian, 252 to 487 million years old. About 0.8 mi of the line.
Schist, gneiss. Age: Paleoproterozoic to Cretaceous, 66 to 2,500 million years old. About 0.8 mi of the line.
Peridotite, serpentinite. Age: Neoproterozoic to Early Jurassic, 175 to 1,000 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.
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 Porterville reaches the Tulare Lake basin by way of the Tule: about 45 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 90% 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 Porterville; river miles along the main stem, rounded.
Porterville has a cold semi-arid climate. Summer afternoons average 96° in July; winter nights fall to about 36° in December. About 12 inches of rain fall in a normal year.
On November 14 Porterville normally reaches 66° and falls to 42°. The record high is 81°, in 2025; the record low 24°, in 1916. The most rain on this date, 0.98 in, fell in 1953.
Normals 1991–2020 and records since 1913 at Lindsay, 10 miles north-northwest. NOAA, through RCC-ACIS.
