The Green Valley 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
78° on Nov. 12, 1990, the hottest reading for this week of the year since 1942. Next is 78° in 1999.
Green Valley’s center stands about 3,040 ft above sea level. Within three miles the land runs from 2,980 ft to 3,320 ft, a difference of 340 ft: rolling country. The highest named summit within 15 miles is Storm Hill, about 5,160 ft, 15 miles west-southwest.
Under the town center the state geologic map shows Alluvium (coarse-detrital, fine-detrital), from the Quaternary, less than 2.6 million years old.
The section below crosses 12 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 13×. 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 7 mi of the line.
Coarse-detrital, clay. Age: Quaternary, less than 2.6 million years old. About 4 mi of the line.
Coarse-detrital, fine-detrital. Age: Quaternary, less than 2.6 million years old. About 4 mi of the line.
Sandstone, siltstone, shale. Age: Late Pennsylvanian to Permian, 273 to 307 million years old. About 3 mi of the line.
Conglomerate. Age: Tertiary, 2.6 to 66 million years old. About 1 mi of the line.
Shale, siltstone. Age: Early Cretaceous, 100 to 145 million years old. About 1 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 6 smaller units along the line are not listed.
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 Green Valley reaches the Gulf of America by way of Rapid Creek, the Cheyenne, the Missouri and the Mississippi: about 2,500 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 Green Valley; river miles along the main stem, rounded.
Green Valley has a dry-winter hot-summer continental climate. Summer afternoons average 86° in July; winter nights fall to about 13° in January. A normal year brings about 48 inches of snow; with the rain, that comes to about 17 inches of water.
On November 14 Green Valley normally reaches 48° and falls to 22°. The record high is 78°, in 1990; the record low −19°, in 1959. The most rain on this date, 0.52 in, fell in 1956.
Normals 1991–2020 and records since 1942 from the Rapid City Area threaded record (Rapid City Regional Airport, 3 miles east, 120 ft higher). NOAA, through RCC-ACIS.
