The Perth 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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73° on Nov. 14, 1989, the hottest reading for this week of the year since 1955. Next is 72° in 2020.
Perth’s center stands about 880 ft above sea level. Within three miles the land runs from 690 ft to 1,010 ft, a difference of 320 ft: rolling country. The highest named summit within 15 miles is Bernhardt Mountain, about 2,310 ft, 11 miles north-northwest.
Under the town center the state geologic map shows Trenton and Black River Groups, undivided (limestone), from the Middle Ordovician, 459 to 471 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 11×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Dolostone, limestone. Age: Early Ordovician, 471 to 487 million years old. About 7 mi of the line.
Limestone. Age: Middle Ordovician, 459 to 471 million years old. About 5 mi of the line.
Black-shale. Age: Middle Ordovician, 459 to 471 million years old. About 3 mi of the line.
Unconsolidated. Age: Quaternary, less than 2.6 million years old. About 2 mi of the line.
Gneiss. Age: Mesoproterozoic, 1 to 1.6 billion years old. About 2 mi of the line.
Dolostone. Age: Cambrian to Early Ordovician, 471 to 497 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. 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 Perth reaches New York Harbor and the Atlantic Ocean by way of Bunn Creek, the Mohawk and the Hudson: about 200 river miles.
160 miles of the trip are on the Hudson.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Perth; river miles along the main stem, rounded.
Perth has a hot-summer humid continental climate. Summer afternoons average 84° in July; winter nights fall to about 14° in January. A normal year brings about 64 inches of snow; with the rain, that comes to about 46 inches of water.
On November 14 Perth normally reaches 49° and falls to 31°. The record high is 73°, in 1989; the record low 11°, in 1996. The most rain on this date, 1.04 in, fell in 1997.
Normals 1991–2020 and records since 1955 at Saratoga Springs 4 SW, 19 miles east, 550 ft lower. NOAA, through RCC-ACIS.
