The Union 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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72° on Nov. 11, 1964, the hottest reading for this week of the year since 1931. Next is 71° in 1971.
Union’s center stands about 940 ft above sea level. Within three miles the land runs from 870 ft to 1,010 ft, a difference of 140 ft: gently rolling country. The highest named summit within 15 miles is Liberty Pole Hill, about 1,110 ft, 6 miles west.
Under the town center the state geologic map shows Ancell Group (sandstone), from the Ordovician, 445 to 487 million years old.
The section below crosses 3 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 62×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Sandstone. Age: Ordovician, 445 to 487 million years old. About 14 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 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 Union reaches the Gulf of America by way of Allen Creek, the Sugar, the Pecatonica, the Rock River and the Mississippi: about 1,680 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Union; river miles along the main stem, rounded.
Union has a hot-summer humid continental climate. Summer afternoons average 83° in July; winter nights fall to about 10° in January. A normal year brings about 36 inches of snow; with the rain, that comes to about 38 inches of water.
On November 14 Union normally reaches 46° and falls to 27°. The record high is 71°, in 1971; the record low 12°, in 1959. The most rain on this date, 0.70 in, fell in 1980.
Normals 1991–2020 and records since 1931 at Stoughton Wwtp, 7 miles northeast, 100 ft lower. NOAA, through RCC-ACIS.
