The St. Peter 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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Mostly sunny; warmer
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5.15 inches of rain fell in two days, the most for this week of the year since records began in 1915. The next wettest, 3.31 inches, fell in 1992.
St. Peter’s center stands about 590 ft above sea level. Within three miles the land runs from 560 ft to 620 ft, a difference of 60 ft: nearly flat ground.
Under the town center the state geologic map shows Mattoon Formation (shale), from the Late Pennsylvanian, 304 to 307 million years old.
The section below crosses 2 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.
Shale. Age: Late Pennsylvanian, 304 to 307 million years old. About 23 mi of the line.
Shale, sandstone, limestone. Age: Late Pennsylvanian, 304 to 307 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.
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 St. Peter reaches the Gulf of America by way of Lone Grove Branch, the East Fork Kaskaskia, the Kaskaskia and the Mississippi: about 1,240 river miles.
Lake on the way: Carlyle Reservoir.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of St. Peter; river miles along the main stem, rounded.
St. Peter has a hot-summer humid continental climate. Summer afternoons average 88° in July; winter nights fall to about 21° in January. A normal year brings about 10 inches of snow; with the rain, that comes to about 46 inches of water.
On November 14 St. Peter normally reaches 55° and falls to 34°. The record high is 80°, in 1999; the record low 10°, in 1986. The most rain on this date, 4.85 in, fell in 1993.
Normals 1991–2020 and records since 1915 at Salem, 17 miles south-southwest. NOAA, through RCC-ACIS.
