The Williamson 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.
Showers likely
Mostly cloudy
Mostly cloudy
Mostly sunny; warmer
Partly cloudy
Partly cloudy
Partly cloudy
78° on Nov. 11, 2020, the hottest reading for this week of the year since 1922. Next is 77° in 1928.
Williamson’s center stands about 450 ft above sea level. Within three miles the land runs from 320 ft to 590 ft, a difference of 270 ft: rolling country. The highest named summit within 15 miles is Johnson Hill, about 690 ft, 10 miles south.
Under the town center the state geologic map shows Decew Dolostone and Rochester Shale, from the Silurian, 428 to 434 million years old.
The section below crosses 6 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 47×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Shale. Age: Silurian, 422 to 428 million years old. About 5 mi of the line.
Dolostone. Age: Silurian, 425 to 428 million years old. About 4 mi of the line.
Shale. Age: Silurian, 428 to 445 million years old. About 2 mi of the line.
Shale. Age: Silurian, 422 to 428 million years old. About 2 mi of the line.
Shale. Age: Late Ordovician to Silurian, 434 to 459 million years old. About 2 mi of the line.
Shale. Age: Silurian, 428 to 434 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 Williamson reaches Lake Ontario by way of Salmon Creek: about 3 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 Williamson; river miles along the main stem, rounded.
Williamson has a warm-summer humid continental climate. Summer afternoons average 79° in July; winter nights fall to about 16° in January. A normal year brings about 105 inches of snow; with the rain, that comes to about 40 inches of water.
On November 14 Williamson normally reaches 48° and falls to 32°. The record high is 70°, in 1994; the record low 12°, in 1996. The most rain on this date, 0.85 in, fell in 1972.
Normals 1991–2020 and records since 1922 at Sodus 1 W, 5 miles east. NOAA, through RCC-ACIS.
