The Mount Vernon 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
Mostly sunny
Partly cloudy
Partly cloudy
Partly cloudy
Partly cloudy
Showers likely
71° on Nov. 14, 1990, the hottest reading for this week of the year since 1936. Next is 68° in 1939.
Mount Vernon’s center stands about 1,200 ft above sea level. Within three miles the land runs from 690 ft to 1,230 ft, a difference of 540 ft: hilly country.
Under the town center the state geologic map shows Lower Ordovician (dolostone, sandstone), from the Early Ordovician, 471 to 487 million years old.
The section below crosses 4 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 31×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Dolostone, sandstone. Age: Early Ordovician, 471 to 487 million years old. About 14 mi of the line.
Sandstone. Age: Cambrian, 487 to 542 million years old. About 8 mi of the line.
Sandstone, siltstone, shale. Age: Cambrian, 487 to 497 million years old. About 1 mi of the line.
Dolostone. Age: Early Ordovician, 471 to 487 million years old. About 0.8 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 Mount Vernon reaches the Gulf of America by way of Trout Creek, the Whitewater and the Mississippi: about 1,730 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Mount Vernon; river miles along the main stem, rounded.
Mount Vernon has a warm-summer humid continental climate. Summer afternoons average 81° in July; winter nights fall to about 8° in January. A normal year brings about 37 inches of snow; with the rain, that comes to about 37 inches of water.
On November 14 Mount Vernon normally reaches 43° and falls to 28°. The record high is 71°, in 1990; the record low 2°, in 1940. The most rain on this date, 0.60 in, fell in 1951.
Normals 1991–2020 and records since 1936 at Alma Dam 4, 12 miles north, 530 ft lower. NOAA, through RCC-ACIS.
