The Granby 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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78° on Nov. 15, 1993, the hottest reading for this week of the year since 1905. Next is 74° in 1909.
Granby’s center stands about 220 ft above sea level. Within three miles the land runs from 170 ft to 640 ft, a difference of 470 ft: hilly country. The highest named summit within 15 miles is Johnson Hill, about 1,480 ft, 12 miles west-northwest.
Under the town center the state geologic map shows New Haven Arkose, from the Late Triassic to Early Jurassic, 175 to 237 million years old.
The section below crosses 10 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 15×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Arkose, siltstone. Age: Early Jurassic, 175 to 202 million years old. About 8 mi of the line.
Arkose. Age: Late Triassic to Early Jurassic, 175 to 237 million years old. About 6 mi of the line.
Quartz-feldspar-schist. Age: Neoproterozoic to Early Cambrian, 521 to 1,000 million years old. About 3 mi of the line.
Hornblende-gneiss, amphibolite. Age: Middle Ordovician, 459 to 471 million years old. About 2 mi of the line.
Schist. Age: Silurian to Devonian, 359 to 445 million years old. About 1 mi of the line.
Gneiss, mica-schist. Age: Middle Ordovician, 459 to 471 million years old. About 0.9 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 4 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 Granby reaches Long Island Sound and the Atlantic Ocean by way of Mountain Brook, East Branch Salmon Brook, the Farmington and the Connecticut: about 80 river miles.
55 miles of the trip are on the Connecticut.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Granby; river miles along the main stem, rounded.
Granby has a hot-summer humid continental climate. Summer afternoons average 85° in July; winter nights fall to about 19° in January. A normal year brings about 52 inches of snow; with the rain, that comes to about 47 inches of water.
On November 14 Granby normally reaches 52° and falls to 33°. The record high is 74°, in 1973; the record low 15°, in 2019. The most rain on this date, 1.87 in, fell in 1972.
Normals 1991–2020 and records since 1905 from the Hartford Area threaded record (Hartford-Bradley International Airport, 6 miles east-southeast). NOAA, through RCC-ACIS.
