The Walnut 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
Partly cloudy; warmer
Mostly sunny
Mostly sunny
Partly cloudy
Mostly sunny
Showers likely
83° on Nov. 13, 1999, the hottest reading for this week of the year since 1893. Next is 75° in 2001.
Walnut’s center stands about 1,330 ft above sea level. Within three miles the land runs from 1,220 ft to 1,350 ft, a difference of 130 ft: gently rolling country.
Under the town center the state geologic map shows Bronson Group (limestone, shale), from the Middle Pennsylvanian to Late Pennsylvanian, 299 to 315 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.
Sandstone, shale. Age: Early Cretaceous to Late Cretaceous, 94 to 113 million years old. About 19 mi of the line.
Limestone, shale. Age: Late Pennsylvanian, 299 to 307 million years old. About 3 mi of the line.
Limestone, shale. Age: Middle Pennsylvanian to Late Pennsylvanian, 299 to 315 million years old. About 0.9 mi of the line.
Limestone, shale. Age: Late Pennsylvanian, 299 to 307 million years old. About 0.8 mi of the line.
Shale, limestone. Age: Middle Pennsylvanian, 307 to 315 million years old. About 0.3 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 Walnut reaches the Gulf of America by way of Walnut Creek, the West Nishnabotna, the Nishnabotna, the Missouri and the Mississippi: about 1,790 river miles.
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 Walnut; river miles along the main stem, rounded.
Walnut has a hot-summer humid continental climate. Summer afternoons average 86° in July; winter nights fall to about 10° in January. A normal year brings about 27 inches of snow; with the rain, that comes to about 37 inches of water.
On November 14 Walnut normally reaches 50° and falls to 26°. The record high is 72°, in 1990; the record low −5°, in 1940. The most rain on this date, 1.44 in, fell in 2024.
Normals 1991–2020 and records since 1893 at Atlantic 1 NE, 12 miles east-southeast, 180 ft lower. NOAA, through RCC-ACIS.
