The Monroe 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.
7° on Nov. 13, 2019, the coldest reading for this week of the year since 1874. Next is 8° in 1933.
Monroe’s center stands about 600 ft above sea level. Within three miles the land runs from 560 ft to 660 ft, a difference of 100 ft: gently rolling country.
Under the town center the state geologic map shows Bass Island Dolomite (dolostone), from the Silurian, 422 to 428 million years old.
The section below crosses 3 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. Age: Early Devonian, 394 to 422 million years old. About 7 mi of the line.
Dolostone. Age: Silurian, 422 to 428 million years old. About 6 mi of the line.
Dolostone. Age: Middle Devonian, 384 to 394 million years old. About 2 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 Monroe reaches Lake Erie by way of the River Raisin: about 4 river miles. From there it moves on through the Great Lakes, over Niagara Falls and down the St. Lawrence to the Atlantic.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Monroe; river miles along the main stem, rounded.
Monroe has a hot-summer humid continental climate. Summer afternoons average 84° in July; winter nights fall to about 19° in January. A normal year brings about 45 inches of snow; with the rain, that comes to about 34 inches of water.
On November 14 Monroe normally reaches 49° and falls to 34°. The record high is 70°, in 1909; the record low 13°, in 1986. The most rain on this date, 1.07 in, fell in 1957.
Normals 1991–2020 and records since 1874 from the Detroit Area threaded record (Detroit Metro Airport, 22 miles north). NOAA, through RCC-ACIS.