The South Heart 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.
Mostly sunny
Mostly sunny; warmer
Partly cloudy
Partly cloudy; cooler
Mostly cloudy; cooler
Mostly cloudy
Chance of showers
75° on Nov. 12, 1999, the hottest reading for this week of the year since 1938. Next is 72° in 1963.
South Heart’s center stands about 2,490 ft above sea level. Within three miles the land runs from 2,440 ft to 2,630 ft, a difference of 190 ft: gently rolling country. The highest named summit within 15 miles is Flagstaff Butte, about 2,870 ft, 14 miles south.
Under the town center the state geologic map shows Sentinel Butte Formation (siltstone, claystone, sandstone), from the Paleocene, 56 to 66 million years old.
The section below crosses 3 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 52×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Siltstone, claystone, sandstone. Age: Paleocene, 56 to 66 million years old. About 19 mi of the line.
Sandstone, claystone, siltstone. Age: Paleocene to Eocene, 34 to 66 million years old. About 3 mi of the line.
Siltstone, claystone, sandstone. Age: Oligocene, 23 to 34 million years old. About 3 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 South Heart reaches the Gulf of America by way of the Heart, the Missouri and the Mississippi: about 2,720 river miles.
Lakes on the way: Lake Oahe, Lake Sharpe, 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 South Heart; river miles along the main stem, rounded.
South Heart has a cold semi-arid climate. Summer afternoons average 84° in July; winter nights fall to about 6° in January. About 16 inches of rain fall in a normal year.
On November 14 South Heart normally reaches 42° and falls to 20°. The record high is 68°, in 2025; the record low −11°, in 2014. The most rain on this date, 0.38 in, fell in 1955.
Normals 1991–2020 and records since 1938 at Dickinson Theodore Roosevelt Regional Airport, 10 miles east-southeast. NOAA, through RCC-ACIS.
