The Rock Dell 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
Mostly sunny; warmer
Partly cloudy
Partly cloudy
Partly cloudy
Partly cloudy
Showers likely
71° on Nov. 16, 1953, the hottest reading for this week of the year since 1886. Next is 71° in 1999.
Rock Dell’s center stands about 1,160 ft above sea level. Within three miles the land runs from 1,120 ft to 1,310 ft, a difference of 190 ft: gently rolling country.
Under the town center the state geologic map shows Upper Ordovician (limestone, dolostone), from the Late Ordovician, 445 to 459 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 49×. 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: Late Ordovician, 445 to 459 million years old. About 14 mi of the line.
Shale, limestone, sandstone. Age: Middle Ordovician to Late Ordovician, 445 to 471 million years old. About 6 mi of the line.
Dolostone, limestone, shale. Age: Middle Devonian, 384 to 394 million years old. About 2 mi of the line.
Dolostone, sandstone. Age: Early Ordovician, 471 to 487 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 Rock Dell reaches the Gulf of America by way of the South Fork Zumbro, the Zumbro and the Mississippi: about 1,820 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Rock Dell; river miles along the main stem, rounded.
Rock Dell has a warm-summer humid continental climate. Summer afternoons average 80° in July; winter nights fall to about 7° in January. A normal year brings about 53 inches of snow; with the rain, that comes to about 35 inches of water.
On November 14 Rock Dell normally reaches 42° and falls to 26°. The record high is 69°, in 2025; the record low −5°, in 1916. The most rain on this date, 0.88 in, fell in 1973.
Normals 1991–2020 and records since 1886 from the Rochester Area threaded record (Rochester International Airport, 7 miles east, 150 ft higher). NOAA, through RCC-ACIS.
