The Jefferson 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
Mostly sunny
Mostly sunny
Partly cloudy
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Chance of showers
−1° on Nov. 16, 1933, the coldest reading for this week of the year since 1893. Next is 0° in 1986.
Jefferson’s center stands about 800 ft above sea level. Within three miles the land runs from 780 ft to 890 ft, a difference of 110 ft: gently rolling country.
Under the town center the state geologic map shows Cambrian, undivided (sandstone), from the Cambrian, 487 to 542 million years old.
The section below crosses 4 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. Age: Early Ordovician, 471 to 487 million years old. About 7 mi of the line.
Dolostone. Age: Ordovician, 445 to 487 million years old. About 7 mi of the line.
Sandstone. Age: Cambrian, 487 to 542 million years old. About 7 mi of the line.
Sandstone. Age: Ordovician, 445 to 487 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 Jefferson reaches the Gulf of America by way of the Rock River and the Mississippi: about 1,680 river miles.
Lake on the way: Lake Koshkonong.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Jefferson; river miles along the main stem, rounded.
Jefferson has a hot-summer humid continental climate. Summer afternoons average 84° in July; winter nights fall to about 11° in January. A normal year brings about 42 inches of snow; with the rain, that comes to about 37 inches of water.
On November 14 Jefferson normally reaches 46° and falls to 29°. The record high is 70°, in 1971; the record low 5°, in 1916. The most rain on this date, 0.77 in, fell in 1897.
Normals 1991–2020 and records since 1893 at Lake Mills Wwtp, 7 miles northwest. NOAA, through RCC-ACIS.
