The Dennis 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
79° on Nov. 16, 1993, the hottest reading for this week of the year since 1965. Next is 78° in 2020.
Dennis’s center stands about 40 ft above sea level. Within three miles the land runs from 0 ft to 70 ft, a difference of 70 ft: gently rolling country.
Under the town center the state geologic map shows Cohansey Formation (sand), from the Middle Miocene, 12 to 14 million years old.
The section below crosses 2 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 64×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Sand. Age: Middle Miocene, 12 to 14 million years old. About 18 mi of the line.
Sand, clay. Age: Late Pliocene, 2.6 to 3.6 million years old. About 4 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 Dennis reaches Delaware Bay and the Atlantic Ocean by way of Dennis Creek: about 6 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Dennis; river miles along the main stem, rounded.
Dennis has a humid subtropical climate. Summer afternoons average 87° in July; winter nights fall to about 23° in January. A normal year brings about 22 inches of snow; with the rain, that comes to about 51 inches of water.
On November 14 Dennis normally reaches 58° and falls to 35°. The record high is 73°, in 1989; the record low 14°, in 1986. The most rain on this date, 3.09 in, fell in 1972.
Normals 1991–2020 and records since 1965 at Estell Manor, 12 miles north. NOAA, through RCC-ACIS.
