The Mount Ayr 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 sunny
Partly cloudy; warmer
Mostly sunny
Sunny
Partly cloudy
Partly cloudy
Mostly sunny
2° on Nov. 17, 1959, the coldest reading for this week of the year since 1900. Next is 2° in 2019.
Mount Ayr’s center stands about 710 ft above sea level. Within three miles the land runs from 660 ft to 760 ft, a difference of 100 ft: gently rolling country.
Under the town center the state geologic map shows New Albany Shale (black-shale), from the Devonian to Carboniferous, 324 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 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.
Limestone, dolostone. Age: Devonian, 359 to 422 million years old. About 13 mi of the line.
Black-shale. Age: Devonian to Carboniferous, 324 to 422 million years old. About 11 mi of the line.
Black-shale. Age: Devonian, 359 to 422 million years old. About 0.3 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 Mount Ayr reaches the Gulf of America by way of Curtis Creek, the Iroquois, the Kankakee, the Illinois and the Mississippi: about 1,590 river miles.
Lake on the way: Peoria Lake.
1,190 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Mount Ayr; river miles along the main stem, rounded.
Mount Ayr has a hot-summer humid continental climate. Summer afternoons average 84° in July; winter nights fall to about 16° in January. A normal year brings about 25 inches of snow; with the rain, that comes to about 40 inches of water.
On November 14 Mount Ayr normally reaches 50° and falls to 32°. The record high is 74°, in 1956; the record low 8°, in 1986. The most rain on this date, 1.56 in, fell in 1959.
Normals 1991–2020 and records since 1900 at Rensselaer Wwtp, 7 miles east-southeast. NOAA, through RCC-ACIS.
