The Allegan 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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72° on Nov. 11, 2012, the hottest reading for this week of the year since 1996. Next is 71° in 2010.
Allegan’s center stands about 660 ft above sea level. Within three miles the land runs from 610 ft to 840 ft, a difference of 230 ft: rolling country. The highest named summit within 15 miles is Beach Hill, about 850 ft, 9 miles north-northwest.
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 24 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 Allegan reaches Lake Michigan by way of the Kalamazoo: about 35 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 Allegan; river miles along the main stem, rounded.
Allegan has a hot-summer humid continental climate. Summer afternoons average 82° in July; winter nights fall to about 20° in January. About 35 inches of rain fall in a normal year.
On November 14 Allegan normally reaches 48° and falls to 34°. The record high is 62°, in 2009; the record low 9°, in 1996. The most rain on this date, 0.45 in, fell in 2021.
Normals 1991–2020 and records since 1996 at Holland Tulip City Airport, 19 miles northwest. NOAA, through RCC-ACIS.
