The Harwinton 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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74° on Nov. 11, 2020, the hottest reading for this week of the year since 1948. Next is 73° in 1993.
Harwinton’s center stands about 830 ft above sea level. Within three miles the land runs from 550 ft to 1,120 ft, a difference of 570 ft: hilly country. The highest named summit within 15 miles is Mohawk Mountain, about 1,680 ft, 13 miles west-northwest.
Under the town center the state geologic map shows Ratlum Mountain Schist (schist, granofels), from the Early Ordovician, 471 to 487 million years old.
The section below crosses 12 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 14×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Gneiss. Age: Cambrian, 487 to 542 million years old. About 6 mi of the line.
Gneiss. Age: Middle Ordovician, 459 to 471 million years old. About 5 mi of the line.
Schist, granofels. Age: Early Ordovician, 471 to 487 million years old. About 3 mi of the line.
Arkose. Age: Late Triassic to Early Jurassic, 175 to 237 million years old. About 2 mi of the line.
Schist. Age: Silurian to Devonian, 359 to 445 million years old. About 2 mi of the line.
Gneiss. Age: Mesoproterozoic, 1 to 1.6 billion 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. 6 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 Harwinton reaches Long Island Sound and the Atlantic Ocean by way of Leadmine Brook, the Naugatuck and the Housatonic: about 50 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Harwinton; river miles along the main stem, rounded.
Harwinton has a warm-summer humid continental climate. Summer afternoons average 82° in July; winter nights fall to about 15° in January. A normal year brings about 59 inches of snow; with the rain, that comes to about 54 inches of water.
On November 14 Harwinton normally reaches 50° and falls to 29°. The record high is 64°, in 2010; the record low 11°, in 2019. The most rain on this date, 0.93 in, fell in 1970.
Normals 1991–2020 and records since 1948 at Bakersville, 6 miles north-northeast, 140 ft lower. NOAA, through RCC-ACIS.
