The St. Johns 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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Partly cloudy; warmer
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8.33 inches of rain fell in two days, the most for this week of the year since records began in 1893. The next wettest, 4.05 inches, fell in 1921.
St. Johns’s center stands about 470 ft above sea level. Within three miles the land runs from 400 ft to 490 ft, a difference of 90 ft: gently rolling country.
Under the town center the state geologic map shows Shelburn-Patoka Formations undivided (shale, limestone), from the Late Pennsylvanian, 304 to 307 million years old.
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, limestone. Age: Late Pennsylvanian, 304 to 307 million years old. About 24 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. Johns reaches the Gulf of America by way of Reese Creek, the Little Muddy, the Big Muddy and the Mississippi: about 1,140 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of St. Johns; river miles along the main stem, rounded.
St. Johns has a hot-summer humid continental climate. Summer afternoons average 87° in July; winter nights fall to about 24° in January. A normal year brings about 12 inches of snow; with the rain, that comes to about 48 inches of water.
On November 14 St. Johns normally reaches 56° and falls to 36°. The record high is 80°, in 1955; the record low 10°, in 1986. The most rain on this date, 6.70 in, fell in 1993.
Normals 1991–2020 and records since 1893 at Du Quoin 4 SE, 4 miles southeast. NOAA, through RCC-ACIS.
