The Garretson 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
Mostly sunny
Partly cloudy
Partly cloudy
Mostly sunny
Showers likely
79° on Nov. 13, 1999, the hottest reading for this week of the year since 1893. Next is 75° in 1953.
Garretson’s center stands about 1,500 ft above sea level. Within three miles the land runs from 1,400 ft to 1,620 ft, a difference of 220 ft: rolling country.
Under the town center the state geologic map shows Sioux Quartzite, from the Paleoproterozoic, 1.6 to 2.5 billion 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 46×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Quartzite. Age: Paleoproterozoic, 1.6 to 2.5 billion years old. About 11 mi of the line.
Quartzite, mudstone. Age: Paleoproterozoic, 1.6 to 2 billion years old. About 9 mi of the line.
Chert, shale, chalk. Age: Early Cretaceous to Late Cretaceous, 66 to 145 million years old. About 4 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 Garretson reaches the Gulf of America by way of Split Rock Creek, the Big Sioux, the Missouri and the Mississippi: about 2,050 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 Garretson; river miles along the main stem, rounded.
Garretson has a hot-summer humid continental climate. Summer afternoons average 85° in July; winter nights fall to about 8° in January. A normal year brings about 45 inches of snow; with the rain, that comes to about 28 inches of water.
On November 14 Garretson normally reaches 46° and falls to 25°. The record high is 73°, in 2025; the record low −17°, in 1959. The most rain on this date, 1.33 in, fell in 1926.
Normals 1991–2020 and records since 1893 from the Sioux Falls Area threaded record (Sioux Falls Foss Field, 16 miles southwest). NOAA, through RCC-ACIS.
