The Rio 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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73° on Nov. 16, 1953, the hottest reading for this week of the year since 1889. Next is 72° in 1964.
Rio’s center stands about 950 ft above sea level. Within three miles the land runs from 820 ft to 1,060 ft, a difference of 240 ft: rolling country. The highest named summit within 15 miles is Cascade Mountain, about 1,310 ft, 14 miles west-northwest.
Under the town center the state geologic map shows Prairie du Chien Group (dolostone), from the Early Ordovician, 471 to 487 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.
Sandstone. Age: Cambrian, 487 to 542 million years old. About 16 mi of the line.
Dolostone. Age: Early Ordovician, 471 to 487 million years old. About 8 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 Rio reaches the Gulf of America by way of Middle Branch Duck Creek, Duck Creek, the Wisconsin and the Mississippi: about 1,740 river miles.
Lake on the way: Lake Wisconsin.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Rio; river miles along the main stem, rounded.
Rio has a hot-summer humid continental climate. Summer afternoons average 82° in July; winter nights fall to about 10° in January. A normal year brings about 39 inches of snow; with the rain, that comes to about 38 inches of water.
On November 14 Rio normally reaches 45° and falls to 29°. The record high is 72°, in 1999; the record low 1°, in 1916. The most rain on this date, 0.63 in, fell in 1902.
Normals 1991–2020 and records since 1889 at Portage Wwtp, 11 miles west-northwest, 160 ft lower. NOAA, through RCC-ACIS.
