The Percy 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.
Sunny
Partly cloudy; warmer
Sunny
Partly cloudy
Mostly sunny
Mostly sunny
Mostly sunny
86° on Nov. 14, 1999, the hottest reading for this week of the year since 1974. Next is 85° in 1989.
Percy’s center stands about 480 ft above sea level. Within three miles the land runs from 410 ft to 520 ft, a difference of 110 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.
The section below crosses 5 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, limestone. Age: Late Pennsylvanian, 304 to 307 million years old. About 12 mi of the line.
Shale, sandstone. Age: Early Pennsylvanian, 315 to 324 million years old. About 4 mi of the line.
Shale, sandstone, coal. Age: Middle Pennsylvanian to Late Pennsylvanian, 304 to 315 million years old. About 4 mi of the line.
Shale, sandstone. Age: Early Pennsylvanian to Middle Pennsylvanian, 307 to 324 million years old. About 3 mi of the line.
Limestone, sandstone, shale. Age: Late Mississippian, 324 to 331 million years old. About 0.4 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 Percy reaches the Gulf of America by way of North Fork Cox Creek, the Marys and the Mississippi: about 1,100 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Percy; river miles along the main stem, rounded.
Percy has a hot-summer humid continental climate. Summer afternoons average 89° in July; winter nights fall to about 24° in January. About 43 inches of rain fall in a normal year, with about 4 inches of snow.
On November 14 Percy normally reaches 56° and falls to 37°. The record high is 86°, in 1999; the record low 9°, in 1986. The most rain on this date, 3.40 in, fell in 1993.
Normals 1991–2020 and records since 1974 at Kaskaskia River Navigation Lock, 18 miles west. NOAA, through RCC-ACIS.
