The Sullivan 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.
Mostly sunny
Mostly sunny; warmer
Mostly sunny
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Partly cloudy
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2° on Nov. 12, 2019, the coldest reading for this week of the year since 1995. Next is 4° in 2014.
Sullivan’s center stands about 860 ft above sea level. Within three miles the land runs from 830 ft to 920 ft, a difference of 90 ft: gently rolling country. The highest named summit within 15 miles is Lapham Hill, about 1,250 ft, 10 miles east.
Under the town center the state geologic map shows Sinnipee Group (dolostone), from the Ordovician, 445 to 487 million years old.
The section below crosses 6 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 54×. 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: Ordovician, 445 to 487 million years old. About 15 mi of the line.
Dolostone. Age: Silurian, 422 to 445 million years old. About 4 mi of the line.
Sandstone. Age: Ordovician, 445 to 487 million years old. About 2 mi of the line.
Dolostone. Age: Early Ordovician, 471 to 487 million years old. About 1 mi of the line.
Shale, dolostone. Age: Ordovician, 445 to 487 million years old. About 0.9 mi of the line.
Sandstone. Age: Cambrian, 487 to 542 million years old. About 0.7 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 Sullivan reaches the Gulf of America by way of the Bark, the Rock River and the Mississippi: about 1,700 river miles.
Lake on the way: Lake Koshkonong.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Sullivan; river miles along the main stem, rounded.
Sullivan has a warm-summer humid continental climate. Summer afternoons average 82° in July; winter nights fall to about 11° in January. A normal year brings about 51 inches of snow; with the rain, that comes to about 38 inches of water.
On November 14 Sullivan normally reaches 46° and falls to 28°. The record high is 69°, in 1999; the record low 10°, in 1996. The most rain on this date, 0.45 in, fell in 2001.
Normals 1991–2020 and records since 1995 at Sullivan 3 SE - Wfo Mkx, 4 miles south-southeast. NOAA, through RCC-ACIS.
