The Twin Grove 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.
Sunny
Mostly sunny; warmer
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2° on Nov. 17, 1959, the coldest reading for this week of the year since 1893. Next is 5° in 1986.
Twin Grove’s center stands about 820 ft above sea level. Within three miles the land runs from 710 ft to 850 ft, a difference of 140 ft: gently rolling country.
Under the town center the state geologic map shows Shelburn-Patoka Formations undivided (shale, limestone), from the Late Pennsylvanian, 304 to 307 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.
Shale, limestone. Age: Late Pennsylvanian, 304 to 307 million years old. About 21 mi of the line.
Shale, sandstone, limestone. Age: Late Pennsylvanian, 304 to 307 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 Twin Grove reaches the Gulf of America by way of Kings Mill Creek, Sugar Creek, Salt Creek, the Sangamon, the Illinois and the Mississippi: about 1,380 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Twin Grove; river miles along the main stem, rounded.
Twin Grove has a hot-summer humid continental climate. Summer afternoons average 86° in July; winter nights fall to about 16° in January. A normal year brings about 20 inches of snow; with the rain, that comes to about 39 inches of water.
On November 14 Twin Grove normally reaches 51° and falls to 31°. The record high is 74°, in 1989; the record low 7°, in 1940. The most rain on this date, 1.10 in, fell in 1926.
Normals 1991–2020 and records since 1893 at Normal 4 NE, 8 miles east-northeast. NOAA, through RCC-ACIS.
