The Jefferson Valley-Yorktown 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 sunny
Partly cloudy
Mostly sunny
Sunny
Mostly sunny
Mostly sunny
77° on Nov. 11, 2020, the hottest reading for this week of the year since 1950. Next is 69° in 2022.
Jefferson Valley-Yorktown’s center stands about 640 ft above sea level. Within three miles the land runs from 360 ft to 860 ft, a difference of 500 ft: hilly country. The highest named summit within 15 miles is South Beacon Mountain, about 1,580 ft, 14 miles north-northwest.
Under the town center the state geologic map shows Biotite-quartz-plagioclase gneiss (biotite-gneiss), from the Mesoproterozoic, 1 to 1.6 billion years old.
The section below crosses 7 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 17×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Biotite-gneiss. Age: Mesoproterozoic, 1 to 1.6 billion years old. About 10 mi of the line.
Pelitic-schist, gneiss, amphibolite. Age: Early Cambrian to Middle Ordovician, 459 to 542 million years old. About 5 mi of the line.
Biotite-gneiss. Age: Mesoproterozoic, 1 to 1.6 billion years old. About 4 mi of the line.
Age: Late Ordovician, 445 to 459 million years old. About 1 mi of the line.
Gneiss. Age: Precambrian to Mesoproterozoic. About 1 mi of the line.
Age: Mesoproterozoic, 1 to 1.6 billion years old. About 0.5 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 1 smaller unit 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 Jefferson Valley-Yorktown reaches New York Harbor and the Atlantic Ocean by way of Shrub Oak Brook, Peekskill Hollow Creek and the Hudson: about 55 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Jefferson Valley-Yorktown; river miles along the main stem, rounded.
Jefferson Valley-Yorktown has a hot-summer humid continental climate. Summer afternoons average 84° in July; winter nights fall to about 17° in January. About 50 inches of rain fall in a normal year.
On November 14 Jefferson Valley-Yorktown normally reaches 53° and falls to 32°. The record high is 68°, in 1964; the record low 17°, in 2019. The most rain on this date, 1.18 in, fell in 1955.
Normals 1991–2020 and records since 1950 at Shrub Oak, 2 miles west-northwest, 180 ft lower. NOAA, through RCC-ACIS.
