The Potosi 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.
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Mostly sunny; warmer
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−3° on Nov. 17, 1959, the coldest reading for this week of the year since 1893. Next is −1° in 1986.
Potosi’s center stands about 930 ft above sea level. Within three miles the land runs from 590 ft to 990 ft, a difference of 400 ft: rolling country. The highest named summit within 15 miles is Sherrill Mound, about 1,220 ft, 7 miles southwest.
Under the town center the state geologic map shows Sinnipee Group (dolostone), from the Ordovician, 445 to 487 million years old.
The section below crosses 8 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 31×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Dolostone. Age: Ordovician, 445 to 487 million years old. About 10 mi of the line.
Sandstone. Age: Ordovician, 445 to 487 million years old. About 6 mi of the line.
Shale, dolostone. Age: Late Ordovician, 447 to 454 million years old. About 3 mi of the line.
Dolostone, limestone. Age: Late Ordovician, 447 to 459 million years old. About 3 mi of the line.
Shale, dolostone. Age: Ordovician, 445 to 487 million years old. About 1 mi of the line.
Dolostone. Age: Early Ordovician, 471 to 487 million years old. About 1 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 2 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 Potosi reaches the Gulf of America by way of Potosi Creek and the Mississippi: about 1,570 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Potosi; river miles along the main stem, rounded.
Potosi has a warm-summer humid continental climate. Summer afternoons average 81° in July; winter nights fall to about 9° in January. A normal year brings about 37 inches of snow; with the rain, that comes to about 38 inches of water.
On November 14 Potosi normally reaches 44° and falls to 28°. The record high is 72°, in 1999; the record low 2°, in 1986. The most rain on this date, 0.81 in, fell in 1902.
Normals 1991–2020 and records since 1893 at Lancaster 4 WSW, 11 miles north-northwest, 110 ft higher. NOAA, through RCC-ACIS.
