The Topsham 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.
Chance of showers
Mostly cloudy
Mostly cloudy
Mostly sunny; warmer
Partly cloudy
Mostly sunny
Partly cloudy
0° on Nov. 17, 2019, the coldest reading for this week of the year since 1948. Next is 4° in 1967.
Topsham’s center stands about 1,880 ft above sea level. Within three miles the land runs from 1,030 ft to 2,210 ft, a difference of 1,180 ft: steep hill country. The highest named summit within 15 miles is Signal Mountain, about 3,360 ft, 5 miles northwest.
Under the town center the state geologic map shows Waits River Formation - carbonaceous phyllite and limestone member (phyllite, limestone), from the Silurian to Early Devonian, 394 to 425 million years old.
The section below crosses 7 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 7×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Phyllite, limestone. Age: Silurian to Early Devonian, 394 to 425 million years old. About 10 mi of the line.
Granite. Age: Devonian, 359 to 422 million years old. About 4 mi of the line.
Metasandstone, metasiltstone, phyllite. Age: Middle Cambrian to Early Ordovician, 485 to 500 million years old. About 4 mi of the line.
Quartzite. Age: Early Devonian, 394 to 422 million years old. About 2 mi of the line.
Quartzite, phyllite, mica-schist. Age: Early Devonian, 404 to 414 million years old. About 2 mi of the line.
Granite. Age: Late Devonian to Early Mississippian, 359 to 369 million years old. About 1 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 1 smaller unit 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 Topsham reaches Long Island Sound and the Atlantic Ocean by way of Powder Spring Brook, Tabor Branch, the Waits and the Connecticut: about 260 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Topsham; river miles along the main stem, rounded.
Topsham has a warm-summer humid continental climate. Summer afternoons average 78° in July; winter nights fall to about 7° in January. About 39 inches of rain fall in a normal year.
On November 14 Topsham normally reaches 44° and falls to 27°. The record high is 65°, in 2011; the record low 5°, in 2018. The most rain on this date, 1.74 in, fell in 2009.
Normals 1991–2020 and records since 1948 at Montpelier - Edward F. Knapp State Airport, 16 miles west-northwest, 780 ft lower. NOAA, through RCC-ACIS.
