The DeKalb 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.
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74° on Nov. 11, 2022, the hottest reading for this week of the year since 1966. Next is 73° in 1989.
DeKalb’s center stands about 890 ft above sea level. Within three miles the land runs from 840 ft to 910 ft, a difference of 70 ft: gently rolling country.
Under the town center the state geologic map shows Maquoketa Formation or Group (shale, limestone), from the Late Ordovician, 445 to 454 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.
Dolostone, limestone. Age: Late Ordovician, 447 to 459 million years old. About 13 mi of the line.
Shale, limestone. Age: Late Ordovician, 445 to 454 million years old. About 11 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 DeKalb reaches the Gulf of America by way of the South Branch Kishwaukee, the Kishwaukee, the Rock River and the Mississippi: about 1,640 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of DeKalb; river miles along the main stem, rounded.
DeKalb has a hot-summer humid continental climate. Summer afternoons average 83° in July; winter nights fall to about 13° in January. A normal year brings about 33 inches of snow; with the rain, that comes to about 37 inches of water.
On November 14 DeKalb normally reaches 47° and falls to 30°. The record high is 73°, in 1999; the record low 2°, in 1986. The most rain on this date, 0.34 in, fell in 1994.
Normals 1991–2020 and records since 1966 at De Kalb, here. NOAA, through RCC-ACIS.
