The Clear Lake 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.
74° on Nov. 15, 1953, the hottest reading for this week of the year since 1931. Next is 74° in 2001.
Clear Lake’s center stands about 1,840 ft above sea level. Within three miles the land runs from 1,820 ft to 1,970 ft, a difference of 150 ft: gently rolling country. The highest named summit within 15 miles is Pleasant Peak, about 2,060 ft, 9 miles north-northwest.
Under the town center the state geologic map shows Pierre Shale (shale, bentonite), from the Late Cretaceous, 66 to 100 million years old.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 25×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Shale, bentonite. Age: Late Cretaceous, 66 to 100 million years old. About 24 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.
Clear Lake has a warm-summer humid continental climate. Summer afternoons average 83° in July; winter nights fall to about 4° in January. A normal year brings about 36 inches of snow; with the rain, that comes to about 23 inches of water.
On November 14 Clear Lake normally reaches 42° and falls to 23°. The record high is 69°, in 1990; the record low −7°, in 2014. The most rain on this date, 0.86 in, fell in 1947.
Normals 1991–2020 and records since 1931 from the Sisseton Area threaded record (Sisseton Municipal Airport, 18 miles east, 680 ft lower). NOAA, through RCC-ACIS.