The Mackinaw City 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.
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Partly cloudy; warmer
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78° on Nov. 11, 2022, the hottest reading for this week of the year since 1891. Next is 71° in 1915.
Mackinaw City’s center stands about 600 ft above sea level. Within three miles the land runs from 570 ft to 740 ft, a difference of 170 ft: gently rolling country. The highest named summit within 15 miles is Billiau Hill, about 780 ft, 13 miles west-southwest.
Under the town center the state geologic map shows Bois Blanc Formation (limestone), from the Early Devonian, 394 to 422 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 48×. 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. Age: Middle Devonian, 384 to 394 million years old. About 6 mi of the line.
Limestone. Age: Early Devonian, 394 to 422 million years old. About 6 mi of the line.
Limestone, sedimentary-breccia. Age: Early Devonian, 394 to 422 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.
Rain that falls on Mackinaw City runs straight into Lake Huron. 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 Mackinaw City; river miles along the main stem, rounded.
Mackinaw City has a warm-summer humid continental climate. Summer afternoons average 77° in July; winter nights fall to about 10° in February. A normal year brings about 88 inches of snow; with the rain, that comes to about 32 inches of water.
On November 14 Mackinaw City normally reaches 44° and falls to 30°. The record high is 64°, in 1999; the record low 11°, in 1933. The most rain on this date, 0.69 in, fell in 1957.
Normals 1991–2020 and records since 1891 at Cheboygan, 15 miles southeast. NOAA, through RCC-ACIS.
