The Monmouth 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.
71° on Nov. 11, 2020, the hottest reading for this week of the year since 1948. Next is 71° in 2022.
Monmouth’s center stands about 290 ft above sea level. Within three miles the land runs from 160 ft to 480 ft, a difference of 320 ft: rolling country. The highest named summit within 15 miles is Bear Mountain, about 1,200 ft, 15 miles northwest.
Under the town center the state geologic map shows Silurian Sangerville Formation (shale, sandstone), from the Silurian, 428 to 434 million years old.
The section below crosses 6 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 38×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Shale, sandstone. Age: Silurian, 428 to 434 million years old. About 7 mi of the line.
Marble. Age: Silurian, 428 to 445 million years old. About 5 mi of the line.
Schist, slate. Age: Silurian, 428 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.
Sandstone. Age: Late Ordovician to Silurian, 428 to 459 million years old. About 3 mi of the line.
Marble, calc-silicate-rock, metasedimentary. Age: Silurian, 428 to 445 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.
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 Monmouth reaches the Atlantic Ocean by way of the Mud Mills Stream, the Wilson Stream, the Jug Stream and the Kennebec: about 70 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Monmouth; river miles along the main stem, rounded.
Monmouth has a warm-summer humid continental climate. Summer afternoons average 80° in July; winter nights fall to about 12° in January. About 42 inches of rain fall in a normal year.
On November 14 Monmouth normally reaches 46° and falls to 31°. The record high is 63°, in 2011; the record low 10°, in 2019. The most rain on this date, 2.41 in, fell in 2009.
Normals 1991–2020 and records since 1948 at Augusta State Airport, 13 miles east-northeast. NOAA, through RCC-ACIS.