The Joliet 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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76° on Nov. 14, 1999, the hottest reading for this week of the year since 1900. Next is 75° in 1953.
Joliet’s center stands about 3,740 ft above sea level. Within three miles the land runs from 3,610 ft to 4,320 ft, a difference of 710 ft: hilly country. The highest named summit within 15 miles is Church Hill, about 4,760 ft, 13 miles southwest.
Under the town center the state geologic map shows Gravel, from the Pleistocene to Holocene, less than 1.8 million years old.
The section below crosses 14 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 14×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Age: Pleistocene to Holocene, less than 1.8 million years old. About 5 mi of the line.
Sandstone, shale. Age: Late Cretaceous, 72 to 84 million years old. About 4 mi of the line.
Sandstone, shale, bentonite. Age: Late Cretaceous, 66 to 84 million years old. About 3 mi of the line.
Shale. Age: Late Cretaceous, 94 to 100 million years old. About 2 mi of the line.
Sandstone. Age: Early Paleocene, 62 to 66 million years old. About 2 mi of the line.
Shale, sandstone. Age: Early Cretaceous, 100 to 113 million years old. About 2 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 8 smaller units 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 Joliet reaches the Gulf of America by way of Rock Creek, the Clarks Fork Yellowstone, the Yellowstone, the Missouri and the Mississippi: about 3,140 river miles.
Lakes on the way: Lake Oahe, Lake Sakakawea, Lake Sharpe and Lake Francis Case.
1,170 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Joliet; river miles along the main stem, rounded.
Joliet has a cold semi-arid climate. Summer afternoons average 87° in July; winter nights fall to about 13° in January. A normal year brings about 30 inches of snow; with the rain, that comes to about 12 inches of water.
On November 14 Joliet normally reaches 46° and falls to 23°. The record high is 76°, in 1999; the record low −9°, in 2014. The most rain on this date, 0.31 in, fell in 1991.
Normals 1991–2020 and records since 1900 at Bridger 2 N, 11 miles south-southeast, 160 ft lower. NOAA, through RCC-ACIS.
