The Opdyke 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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6° on Nov. 13, 2019, the coldest reading for this week of the year since 1895. Next is 8° in 1959.
Opdyke’s center stands about 510 ft above sea level. Within three miles the land runs from 440 ft to 590 ft, a difference of 150 ft: gently rolling country.
Under the town center the state geologic map shows Mattoon Formation (shale), 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. 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 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 Opdyke reaches the Gulf of America by way of Auxier Creek, the Skillet Fork, the Little Wabash, the Ohio and the Mississippi: about 1,200 river miles.
970 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Opdyke; river miles along the main stem, rounded.
Opdyke has a hot-summer humid continental climate. Summer afternoons average 86° in July; winter nights fall to about 22° in January. A normal year brings about 10 inches of snow; with the rain, that comes to about 45 inches of water.
On November 14 Opdyke normally reaches 54° and falls to 35°. The record high is 78°, in 1964; the record low 8°, in 1986. The most rain on this date, 4.41 in, fell in 1993.
Normals 1991–2020 and records since 1895 at Mount Vernon Outland Airport, 6 miles northwest. NOAA, through RCC-ACIS.
