The Philadelphia 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.
Sunny
Partly cloudy; warmer
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Mostly sunny
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2° on Nov. 17, 1959, the coldest reading for this week of the year since 1893. Next is 3° in 1940.
Philadelphia’s center stands about 700 ft above sea level. Within three miles the land runs from 550 ft to 740 ft, a difference of 190 ft: gently rolling country.
Under the town center the state geologic map shows Osagean Series (limestone), from the Carboniferous, 324 to 359 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.
Limestone. Age: Carboniferous, 324 to 359 million years old. About 23 mi of the line.
Limestone, siltstone. Age: Carboniferous, 324 to 359 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.
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 Philadelphia reaches the Gulf of America by way of the North River and the Mississippi: about 1,320 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Philadelphia; river miles along the main stem, rounded.
Philadelphia has a hot-summer humid continental climate. Summer afternoons average 86° in July; winter nights fall to about 18° in January. A normal year brings about 18 inches of snow; with the rain, that comes to about 40 inches of water.
On November 14 Philadelphia normally reaches 52° and falls to 33°. The record high is 76°, in 1971; the record low 3°, in 1940. The most rain on this date, 1.60 in, fell in 1926.
Normals 1991–2020 and records since 1893 at Steffenville, 12 miles northwest. NOAA, through RCC-ACIS.
