The Colchester 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
Partly cloudy; warmer
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Mostly sunny
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79° on Nov. 11, 1964, the hottest reading for this week of the year since 1895. Next is 78° in 1896.
Colchester’s center stands about 700 ft above sea level. Within three miles the land runs from 570 ft to 730 ft, a difference of 160 ft: gently rolling country.
Under the town center the state geologic map shows Carbondale Formation (shale, sandstone, coal), from the Middle Pennsylvanian to Late Pennsylvanian, 304 to 315 million years old.
The section below crosses 5 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, coal. Age: Middle Pennsylvanian to Late Pennsylvanian, 304 to 315 million years old. About 11 mi of the line.
Shale, sandstone. Age: Early Pennsylvanian to Middle Pennsylvanian, 307 to 324 million years old. About 4 mi of the line.
Limestone. Age: Middle Mississippian, 331 to 347 million years old. About 4 mi of the line.
Limestone. Age: Middle Mississippian, 331 to 347 million years old. About 4 mi of the line.
Limestone. Age: Early Mississippian to Middle Mississippian, 331 to 359 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.
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 Colchester reaches the Gulf of America by way of the East Fork La Moine, the La Moine, the Illinois and the Mississippi: about 1,360 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Colchester; river miles along the main stem, rounded.
Colchester has a hot-summer humid continental climate. Summer afternoons average 85° in July; winter nights fall to about 15° in January. About 39 inches of rain fall in a normal year.
On November 14 Colchester normally reaches 50° and falls to 31°. The record high is 77°, in 1989; the record low 5°, in 1940. The most rain on this date, 1.15 in, fell in 1926.
Normals 1991–2020 and records since 1895 at La Harpe, 15 miles northwest. NOAA, through RCC-ACIS.
