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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3° on Nov. 17, 1967, the coldest reading for this week of the year since 1893. Next is 6° in 1933.
Rochester’s center stands about 230 ft above sea level. Within three miles the land runs from 160 ft to 490 ft, a difference of 330 ft: rolling country. The highest named summit within 15 miles is Parker Mountain, about 1,410 ft, 10 miles west.
Under the town center the state geologic map shows Perry Mountain Formation, undivided (quartzite, metasedimentary), from the Silurian, 422 to 445 million years old.
The section below crosses 11 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 19×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Quartzite, metasedimentary. Age: Silurian, 422 to 445 million years old. About 5 mi of the line.
Granite. Age: Late Devonian, 359 to 384 million years old. About 3 mi of the line.
Gneiss. Age: Neoproterozoic to Silurian, 422 to 1,000 million years old. About 3 mi of the line.
Metagraywacke. Age: Early Devonian, 410 to 414 million years old. About 3 mi of the line.
Pelitic-schist, metasandstone. Age: Silurian, 434 to 445 million years old. About 3 mi of the line.
Metasandstone, phyllite. Age: Neoproterozoic to Silurian, 422 to 1,000 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. 5 smaller units along the line are not listed.
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 Atlantic Ocean by way of the Cocheco and the Piscataqua: about 25 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 warm-summer humid continental climate. Summer afternoons average 83° in July; winter nights fall to about 15° in January. A normal year brings about 39 inches of snow; with the rain, that comes to about 45 inches of water.
On November 14 Rochester normally reaches 49° and falls to 31°. The record high is 71°, in 1989; the record low 6°, in 2019. The most rain on this date, 2.14 in, fell in 1937.
Normals 1991–2020 and records since 1893 at Durham, 11 miles south, 150 ft lower. NOAA, through RCC-ACIS.
