The Roscommon 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 cloudy
Mostly cloudy; warmer
Mostly sunny
Mostly sunny
Partly cloudy
Partly cloudy
Partly cloudy
−11° on Nov. 16, 1933, the coldest reading for this week of the year since 1913. Next is 0° in 1940.
Roscommon’s center stands about 1,130 ft above sea level. Within three miles the land runs from 1,130 ft to 1,280 ft, a difference of 150 ft: gently rolling country. The highest named summit within 15 miles is Cote Dame Marie, about 1,540 ft, 12 miles northwest.
Under the town center the state geologic map shows Michigan Formation (shale), from the Carboniferous, 324 to 359 million years old.
The section below crosses 2 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 56×. 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. Age: Carboniferous, 324 to 359 million years old. About 18 mi of the line.
Sandstone. Age: Carboniferous, 324 to 359 million years old. About 6 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 Roscommon reaches Lake Huron by way of Robinson Creek, the South Branch Au Sable and the Au Sable: about 120 river miles. From there it moves on through the Great Lakes, over Niagara Falls and down the St. Lawrence to the Atlantic.
100 miles of the trip are on the Au Sable.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Roscommon; river miles along the main stem, rounded.
Roscommon has a warm-summer humid continental climate. Summer afternoons average 81° in July; winter nights fall to about 11° in January. A normal year brings about 66 inches of snow; with the rain, that comes to about 30 inches of water.
On November 14 Roscommon normally reaches 44° and falls to 28°. The record high is 63°, in 1953; the record low 0°, in 1940. The most rain on this date, 0.79 in, fell in 1958.
Normals 1991–2020 and records since 1913 from the Houghton Lake Area threaded record (Houghton Lake Roscommon County Airport, 10 miles south-southwest). NOAA, through RCC-ACIS.
