The Rosemont 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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79° on Nov. 15, 1993, the hottest reading for this week of the year since 1940. Next is 78° in 2005.
Rosemont’s center stands about 390 ft above sea level. Within three miles the land runs from 130 ft to 470 ft, a difference of 340 ft: rolling country. The highest named summit within 15 miles is Diamond Rock Hill, about 700 ft, 10 miles west-northwest.
The section below crosses 15 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 31×. 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.
Sand. Age: Miocene, 5.3 to 23 million years old. About 3 mi of the line.
Schist, phyllite. Age: Paleozoic, 252 to 542 million years old. About 2 mi of the line.
Sand, clay. Age: Pleistocene, less than 2.6 million years old. About 2 mi of the line.
Gneiss. Age: Precambrian. About 2 mi of the line.
Limestone. Age: Cambrian, 487 to 542 million years old. About 2 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 9 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 Rosemont reaches Delaware Bay and the Atlantic Ocean by way of Mill Creek, the Schuylkill and the Delaware: about 80 river miles.
60 miles of the trip are on the Delaware.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Rosemont; river miles along the main stem, rounded.
Rosemont has a humid subtropical climate. Summer afternoons average 89° in July; winter nights fall to about 28° in January. A normal year brings about 16 inches of snow; with the rain, that comes to about 51 inches of water.
On November 14 Rosemont normally reaches 57° and falls to 42°. The record high is 74°, in 1955; the record low 26°, in 1986. The most rain on this date, 1.09 in, fell in 1940.
Normals 1991–2020 and records since 1940 from the Philadelphia Center City Area threaded record (Philadelphia Franklin Institute, 10 miles east-southeast, 330 ft lower). NOAA, through RCC-ACIS.
