The Croghan 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
Mostly cloudy; warmer
Partly cloudy
Mostly sunny; warmer
Partly cloudy
Partly cloudy
Partly cloudy
74° on Nov. 11, 2020, the hottest reading for this week of the year since 1891. Next is 69° in 1964.
Croghan’s center stands about 840 ft above sea level. Within three miles the land runs from 760 ft to 1,010 ft, a difference of 250 ft: rolling country. The highest named summit within 15 miles is Bald Mountain, about 1,660 ft, 13 miles northeast.
Under the town center the state geologic map shows Biotite and/or hornblende granite gneiss, from the Mesoproterozoic, 1 to 1.6 billion years old.
The section below crosses 11 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 20×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Unconsolidated. Age: Quaternary, less than 2.6 million years old. About 10 mi of the line.
Gneiss. Age: Mesoproterozoic, 1 to 1.6 billion years old. About 4 mi of the line.
Limestone. Age: Middle Ordovician, 459 to 471 million years old. About 3 mi of the line.
Gneiss. Age: Mesoproterozoic, 1 to 1.6 billion years old. About 2 mi of the line.
Metasedimentary, migmatite. Age: Mesoproterozoic, 1 to 1.6 billion years old. About 1 mi of the line.
Siltstone, shale. Age: Late Ordovician, 445 to 459 million years old. About 0.9 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 5 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 Croghan reaches Lake Ontario by way of the Beaver and the Black River: about 50 river miles. From the lake it goes down the St. Lawrence to the Atlantic.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Croghan; river miles along the main stem, rounded.
Croghan has a warm-summer humid continental climate. Summer afternoons average 78° in July; winter nights fall to about 8° in January. A normal year brings about 127 inches of snow; with the rain, that comes to about 42 inches of water.
On November 14 Croghan normally reaches 45° and falls to 28°. The record high is 65°, in 1930; the record low 1°, in 2019. The most rain on this date, 1.06 in, fell in 1925.
Normals 1991–2020 and records since 1891 at Lowville, 8 miles south-southwest. NOAA, through RCC-ACIS.
