The Clarks 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
Mostly sunny; warmer
Mostly sunny
Partly cloudy
Mostly sunny
Partly cloudy
Showers likely
85° on Nov. 15, 2025, the hottest reading for this week of the year since 1878. Next is 82° in 1949.
Clarks’s center stands about 1,630 ft above sea level. Within three miles the land runs from 1,600 ft to 1,650 ft, a difference of 50 ft: nearly flat ground.
Under the town center the state geologic map shows Niobrara Formation (limestone, shale), from the Late Cretaceous, 66 to 100 million years old.
The section below crosses 2 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 64×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Limestone, shale. Age: Late Cretaceous, 66 to 100 million years old. About 24 mi of the line.
Shale. Age: Late Cretaceous, 66 to 100 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 Clarks reaches the Gulf of America by way of Silver Creek, the Platte, the Missouri and the Mississippi: about 1,890 river miles.
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 Clarks; river miles along the main stem, rounded.
Clarks has a hot-summer humid continental climate. Summer afternoons average 86° in July; winter nights fall to about 14° in January. A normal year brings about 29 inches of snow; with the rain, that comes to about 28 inches of water.
On November 14 Clarks normally reaches 51° and falls to 27°. The record high is 72°, in 2025; the record low −6°, in 1940. The most rain on this date, 0.27 in, fell in 1968.
Normals 1991–2020 and records since 1878 at Central City, 11 miles west-southwest. NOAA, through RCC-ACIS.
