The Rochester 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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−4° on Nov. 17, 1959, the coldest reading for this week of the year since 1893. Next is 3° in 2019.
Rochester’s center stands about 670 ft above sea level. Within three miles the land runs from 640 ft to 810 ft, a difference of 170 ft: gently rolling country.
Under the town center the state geologic map shows Wapsipinicon Group (dolostone, limestone), from the Middle Devonian, 384 to 394 million years old.
The section below crosses 4 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.
Dolostone, limestone. Age: Middle Devonian, 384 to 394 million years old. About 10 mi of the line.
Dolostone, mudstone. Age: Silurian, 425 to 434 million years old. About 8 mi of the line.
Dolostone. Age: Silurian, 431 to 440 million years old. About 4 mi of the line.
Limestone, dolostone. Age: Middle Devonian to Late Devonian, 374 to 388 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.
A raindrop that lands in Rochester reaches the Gulf of America by way of Rock Creek, the Cedar River, the Iowa and the Mississippi: about 1,480 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Rochester; river miles along the main stem, rounded.
Rochester has a hot-summer humid continental climate. Summer afternoons average 84° in July; winter nights fall to about 12° in January. A normal year brings about 28 inches of snow; with the rain, that comes to about 38 inches of water.
On November 14 Rochester normally reaches 48° and falls to 28°. The record high is 73°, in 1990; the record low 4°, in 1916. The most rain on this date, 0.86 in, fell in 1902.
Normals 1991–2020 and records since 1893 at Iowa City, 18 miles west-southwest. NOAA, through RCC-ACIS.
