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
Partly cloudy
Partly cloudy
Partly cloudy
Partly cloudy
Chance of showers
−2° on Nov. 17, 1959, the coldest reading for this week of the year since 1936. Next is 1° in 1986.
Jefferson’s center stands about 690 ft above sea level. Within three miles the land runs from 610 ft to 1,140 ft, a difference of 530 ft: hilly country. The highest named summit within 15 miles is Bunker Hill, about 1,200 ft, 12 miles northeast.
The section below crosses 7 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 27×. 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, sandstone. Age: Early Ordovician, 471 to 487 million years old. About 8 mi of the line.
Sandstone. Age: Ordovician, 445 to 487 million years old. About 6 mi of the line.
Sandstone, siltstone, shale. Age: Middle Cambrian to Cambrian, 487 to 521 million years old. About 4 mi of the line.
Sandstone, siltstone, shale. Age: Cambrian, 487 to 497 million years old. About 3 mi of the line.
Dolostone. Age: Early Ordovician, 471 to 487 million years old. About 2 mi of the line.
Dolostone. Age: Ordovician, 445 to 487 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. 1 smaller unit along the line are not listed.
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 Winnebago Creek, Minnesota Slough and the Mississippi: about 1,660 river miles.
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 35 inches of snow; with the rain, that comes to about 38 inches of water.
On November 14 Jefferson normally reaches 46° and falls to 30°. The record high is 69°, in 1990; the record low 6°, in 1959. The most rain on this date, 0.31 in, fell in 2008.
Normals 1991–2020 and records since 1936 at Genoa Dam 8, 5 miles north-northeast. NOAA, through RCC-ACIS.
