The Marlborough 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 cloudy
Mostly sunny
Partly cloudy
Mostly sunny
Mostly sunny
Mostly sunny
Mostly sunny
5° on Nov. 17, 1996, the coldest reading for this week of the year since 1904. Next is 6° in 1924.
Marlborough’s center stands about 450 ft above sea level. Within three miles the land runs from 270 ft to 770 ft, a difference of 500 ft: hilly country. The highest named summit within 15 miles is Grant Hill, about 970 ft, 13 miles north-northeast.
Under the town center the state geologic map shows Hebron Gneiss (schist, calc-silicate-rock), from the Neoproterozoic, 542 to 1,000 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 21×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Schist, calc-silicate-rock. Age: Neoproterozoic, 542 to 1,000 million years old. About 5 mi of the line.
Arkose, siltstone. Age: Early Jurassic, 175 to 202 million years old. About 4 mi of the line.
Biotite-gneiss. Age: Devonian, 359 to 422 million years old. About 3 mi of the line.
Gneiss. Age: Middle Ordovician, 459 to 471 million years old. About 3 mi of the line.
Gneiss, schist. Age: Neoproterozoic, 542 to 1,000 million years old. About 2 mi of the line.
Schist. Age: Neoproterozoic, 542 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. 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 Marlborough reaches Long Island Sound and the Atlantic Ocean by way of Lyman Brook, the Blackledge, the Salmon and the Connecticut: about 30 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Marlborough; river miles along the main stem, rounded.
Marlborough has a hot-summer humid continental climate. Summer afternoons average 85° in July; winter nights fall to about 20° in January. About 43 inches of rain fall in a normal year.
On November 14 Marlborough normally reaches 53° and falls to 35°. The record high is 71°, in 1959; the record low 15°, in 1996. The most rain on this date, 1.07 in, fell in 1940.
Normals 1991–2020 and records since 1904 at Hartford Brainard Field, 12 miles west-northwest, 430 ft lower. NOAA, through RCC-ACIS.
