The Acton 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; warmer
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76° on Nov. 11, 2020, the hottest reading for this week of the year since 1953. Next is 73° in 2022.
Acton’s center stands about 740 ft above sea level. Within three miles the land runs from 480 ft to 950 ft, a difference of 470 ft: hilly country. The highest named summit within 15 miles is Copple Crown Mountain, about 1,860 ft, 10 miles west.
Under the town center the state geologic map shows Devonian - Silurian Rindgemere Formation upper member (sandstone, mudstone), from the Silurian to Devonian, 359 to 445 million years old.
The section below crosses 9 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 12×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Mudstone, limestone. Age: Silurian to Devonian, 359 to 445 million years old. About 10 mi of the line.
Calc-silicate-rock. Age: Silurian, 434 to 445 million years old. About 4 mi of the line.
Granite. Age: Devonian, 359 to 422 million years old. About 3 mi of the line.
Granite. Age: Early Cretaceous, 100 to 145 million years old. About 3 mi of the line.
Metaclastic. Age: Silurian, 434 to 445 million years old. About 2 mi of the line.
Gabbro. Age: Cretaceous, 66 to 145 million years old. About 0.7 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 3 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 Acton reaches the Atlantic Ocean by way of the Salmon Falls and the Piscataqua: about 50 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Acton; river miles along the main stem, rounded.
Acton has a warm-summer humid continental climate. Summer afternoons average 81° in July; winter nights fall to about 10° in January. About 51 inches of rain fall in a normal year.
On November 14 Acton normally reaches 49° and falls to 27°. The record high is 71°, in 1989; the record low 9°, in 2019. The most rain on this date, 1.60 in, fell in 2018.
Normals 1991–2020 and records since 1953 at Sanford 2 NNW, 8 miles southeast, 450 ft lower. NOAA, through RCC-ACIS.
