The Devon 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.
Partly cloudy
Mostly sunny; warmer
Partly cloudy
Sunny
Sunny
Mostly sunny
Mostly sunny
78° on Nov. 15, 1993, the hottest reading for this week of the year since 1893. Next is 77° in 1973.
Devon’s center stands about 510 ft above sea level. Within three miles the land runs from 140 ft to 560 ft, a difference of 420 ft: hilly country. The highest named summit within 15 miles is Diamond Rock Hill, about 700 ft, 5 miles west-northwest.
Under the town center the state geologic map shows Octoraro Formation (schist, phyllite), from the Paleozoic, 252 to 542 million years old.
The section below crosses 16 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 30×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Mica-schist. Age: Paleozoic, 252 to 542 million years old. About 6 mi of the line.
Arkose. Age: Triassic, 202 to 252 million years old. About 5 mi of the line.
Gneiss. Age: Precambrian. About 3 mi of the line.
Schist, phyllite. Age: Paleozoic, 252 to 542 million years old. About 2 mi of the line.
Gneiss. Age: Precambrian. About 2 mi of the line.
Mudstone. Age: Triassic, 202 to 252 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. 10 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 Devon reaches Delaware Bay and the Atlantic Ocean by way of Darby Creek and the Delaware: about 75 river miles.
50 miles of the trip are on the Delaware.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Devon; river miles along the main stem, rounded.
Devon has a hot-summer humid continental climate. Summer afternoons average 88° in July; winter nights fall to about 23° in January. About 45 inches of rain fall in a normal year.
On November 14 Devon normally reaches 56° and falls to 35°. The record high is 75°, in 1955; the record low 19°, in 1950. The most rain on this date, 2.56 in, fell in 1972.
Normals 1991–2020 and records since 1893 at Phoenixville 1 E, 6 miles north-northwest, 370 ft lower. NOAA, through RCC-ACIS.
