The Okaton 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.
Partly cloudy
Sunny; warmer
Mostly sunny
Partly cloudy
Partly cloudy; cooler
Partly cloudy
Chance of showers
−21° on Nov. 14, 1959, the coldest reading for this week of the year since 1907. Next is −13° in 1940.
Okaton’s center stands about 2,330 ft above sea level. Within three miles the land runs from 2,060 ft to 2,390 ft, a difference of 330 ft: rolling country. The highest named summit within 15 miles is White Clay Butte, about 2,500 ft, 11 miles east-northeast.
Under the town center the state geologic map shows Pierre Shale (shale, bentonite), from the Late Cretaceous, 66 to 100 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 36×. 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 19 mi of the line.
Coarse-detrital, clay. Age: Quaternary, less than 2.6 million years old. About 3 mi of the line.
Silt, sand. Age: Quaternary, less than 2.6 million years old. About 2 mi of the line.
Coarse-detrital, fine-detrital. Age: Quaternary, 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.
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 Okaton reaches the Gulf of America by way of the White River, the Missouri and the Mississippi: about 2,280 river miles.
Lakes on the way: Lake Francis Case and Lewis and Clark Lake.
1,170 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Okaton; river miles along the main stem, rounded.
Okaton has a hot-summer humid continental climate. Summer afternoons average 87° in July; winter nights fall to about 12° in January. A normal year brings about 49 inches of snow; with the rain, that comes to about 22 inches of water.
On November 14 Okaton normally reaches 46° and falls to 25°. The record high is 75°, in 1975; the record low −21°, in 1959. The most rain on this date, 0.40 in, fell in 1956.
Normals 1991–2020 and records since 1907 at Murdo, 9 miles east. NOAA, through RCC-ACIS.
