The Yankton 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
Partly cloudy
Partly cloudy; cooler
Showers likely
83° on Nov. 14, 2025, the hottest reading for this week of the year since 1932. Next is 77° in 2021.
Yankton’s center stands about 1,210 ft above sea level. Within three miles the land runs from 1,150 ft to 1,310 ft, a difference of 160 ft: gently rolling country.
Under the town center the state geologic map shows Carlile Shale, from the Late Cretaceous, 66 to 100 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 45×. 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. Age: Late Cretaceous, 66 to 100 million years old. About 5 mi of the line.
Shale, bentonite. Age: Late Cretaceous, 66 to 100 million years old. About 5 mi of the line.
Chalk, marlstone, shale. Age: Late Cretaceous, 66 to 100 million years old. About 5 mi of the line.
Shale. Age: Late Cretaceous, 66 to 100 million years old. About 4 mi of the line.
Limestone, shale. Age: Late Cretaceous, 66 to 100 million years old. About 3 mi of the line.
Fine-detrital, siltstone, conglomerate-sandstone. Age: Miocene to Pliocene, 2.6 to 23 million years old. About 2 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 Yankton reaches the Gulf of America by way of Marne Creek, the Missouri and the Mississippi: about 1,960 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 Yankton; river miles along the main stem, rounded.
Yankton has a hot-summer humid continental climate. Summer afternoons average 87° in July; winter nights fall to about 10° in January. A normal year brings about 38 inches of snow; with the rain, that comes to about 29 inches of water.
Normals 1991–2020 and records since 1932 at Yankton Municipal Airport, 3 miles north-northeast. NOAA, through RCC-ACIS.
