The Arrowsmith 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
Sunny
Partly cloudy
Mostly sunny
Partly cloudy
Partly cloudy
2° on Nov. 17, 1959, the coldest reading for this week of the year since 1893. Next is 5° in 1986.
Arrowsmith’s center stands about 880 ft above sea level. Within three miles the land runs from 820 ft to 900 ft, a difference of 80 ft: gently rolling country.
Under the town center the state geologic map shows Bond Formation (shale, sandstone, limestone), from the Late Pennsylvanian, 304 to 307 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 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, sandstone, limestone. Age: Late Pennsylvanian, 304 to 307 million years old. About 14 mi of the line.
Shale, limestone. Age: Late Pennsylvanian, 304 to 307 million years old. About 6 mi of the line.
Shale. 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 Arrowsmith reaches the Gulf of America by way of the Sangamon, the Illinois and the Mississippi: about 1,520 river miles.
1,190 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Arrowsmith; river miles along the main stem, rounded.
Arrowsmith 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 Arrowsmith 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, 18 miles west-northwest. NOAA, through RCC-ACIS.
