The Delaware 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.
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75° on Nov. 16, 1993, the hottest reading for this week of the year since 1893. Next is 74° in 1902.
Delaware’s center stands about 300 ft above sea level. Within three miles the land runs from 240 ft to 770 ft, a difference of 530 ft: hilly country. The highest named summit within 15 miles is Kittatinny Mountain, about 1,540 ft, 7 miles west-northwest.
Under the town center the state geologic map shows Ramseyburg Member (graywacke, siltstone), from the Middle Ordovician to Late Ordovician, 445 to 471 million years old.
The section below crosses 14 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 14×. 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. Age: Ordovician, 445 to 487 million years old. About 5 mi of the line.
Shale, slate. Age: Ordovician, 445 to 487 million years old. About 3 mi of the line.
Graywacke, siltstone. Age: Middle Ordovician to Late Ordovician, 445 to 471 million years old. About 3 mi of the line.
Sandstone, conglomerate. Age: Silurian, 422 to 445 million years old. About 3 mi of the line.
Dolostone. Age: Cambrian to Early Ordovician, 471 to 497 million years old. About 2 mi of the line.
Dolostone. Age: Early Ordovician, 471 to 487 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. 8 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 Delaware reaches Delaware Bay and the Atlantic Ocean by way of the Delaware: about 170 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Delaware; river miles along the main stem, rounded.
Delaware has a hot-summer humid continental climate. Summer afternoons average 84° in July; winter nights fall to about 18° in January. A normal year brings about 23 inches of snow; with the rain, that comes to about 48 inches of water.
On November 14 Delaware normally reaches 53° and falls to 30°. The record high is 72°, in 1964; the record low 11°, in 1905. The most rain on this date, 0.90 in, fell in 1940.
Normals 1991–2020 and records since 1893 from the Belvidere Area threaded record (Belvidere Bridge, 4 miles south). NOAA, through RCC-ACIS.
