The Mackinaw 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; warmer
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5° on Nov. 12, 2019, the coldest reading for this week of the year since 1935. Next is 12° in 1996.
Mackinaw’s center stands about 670 ft above sea level. Within three miles the land runs from 570 ft to 790 ft, a difference of 220 ft: rolling country.
Under the town center the state geologic map shows Carbondale Formation (shale, sandstone, coal), from the Middle Pennsylvanian to Late Pennsylvanian, 304 to 315 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 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 20 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.
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 Mackinaw reaches the Gulf of America by way of the Mackinaw, the Illinois and the Mississippi: about 1,380 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Mackinaw; river miles along the main stem, rounded.
Mackinaw has a hot-summer humid continental climate. Summer afternoons average 86° in July; winter nights fall to about 17° in January. A normal year brings about 22 inches of snow; with the rain, that comes to about 38 inches of water.
Normals 1991–2020 and records since 1935 at Congerville 2 NW, 8 miles northeast. NOAA, through RCC-ACIS.
