The South Londonderry 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.
Mostly cloudy
Partly cloudy; warmer
Partly cloudy
Sunny
Sunny
Mostly sunny
Mostly sunny
76° on Nov. 15, 1973, the hottest reading for this week of the year since 1888. Next is 76° in 1993.
South Londonderry’s center stands about 530 ft above sea level. Within three miles the land runs from 440 ft to 830 ft, a difference of 390 ft: rolling country. The highest named summit within 15 miles is Governor Dick Hill, about 1,190 ft, 5 miles east.
Under the town center the state geologic map shows Hammer Creek Formation (sandstone), from the Triassic, 202 to 252 million years old.
The section below crosses 9 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 23×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Sandstone. Age: Triassic, 202 to 252 million years old. About 9 mi of the line.
Siltstone-mudstone, shale. Age: Triassic, 202 to 252 million years old. About 7 mi of the line.
Conglomerate, sandstone. Age: Triassic, 202 to 252 million years old. About 3 mi of the line.
Basalt. Age: Jurassic, 145 to 202 million years old. About 2 mi of the line.
Limestone. Age: Ordovician, 445 to 487 million years old. About 1 mi of the line.
Limestone, dolostone. Age: Ordovician, 445 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. 3 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 South Londonderry reaches Chesapeake Bay and the Atlantic Ocean by way of Little Conewago Creek, Conewago Creek and the Susquehanna: about 75 river miles.
Lake on the way: Lake Aldred.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of South Londonderry; river miles along the main stem, rounded.
South Londonderry has a hot-summer humid continental climate. Summer afternoons average 87° in July; winter nights fall to about 23° in January. A normal year brings about 30 inches of snow; with the rain, that comes to about 44 inches of water.
On November 14 South Londonderry normally reaches 54° and falls to 36°. The record high is 74°, in 1989; the record low 19°, in 1986. The most rain on this date, 1.74 in, fell in 1995.
Normals 1991–2020 and records since 1888 from the Middletown-Harrisburg Area threaded record (Middletown Harrisburg Int'L Airport, 13 miles west-southwest, 230 ft lower). NOAA, through RCC-ACIS.
