The Old Tappan 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
Mostly sunny
Sunny
Sunny
Mostly sunny
Mostly sunny
77° on Nov. 15, 1993, the hottest reading for this week of the year since 1969. Next is 76° in 1973.
Old Tappan’s center stands about 100 ft above sea level. Within three miles the land runs from 20 ft to 280 ft, a difference of 260 ft: rolling country. The highest named summit within 15 miles is Breakneck Mountain, about 1,290 ft, 14 miles north-northwest.
Under the town center the state geologic map shows Passaic Formation Sandstone and Siltstone facies (sandstone, siltstone), from the Early Jurassic to Late Jurassic, 145 to 202 million 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 22×. 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, siltstone. Age: Early Jurassic to Late Jurassic, 145 to 202 million years old. About 5 mi of the line.
Conglomerate-sandstone. Age: Early Jurassic to Late Jurassic, 145 to 202 million years old. About 3 mi of the line.
Gneiss. Age: Precambrian to Mesoproterozoic. About 3 mi of the line.
Conglomerate. Age: Late Triassic, 202 to 237 million years old. About 3 mi of the line.
Sandstone. Age: Late Triassic, 202 to 237 million years old. About 2 mi of the line.
Conglomerate, sandstone. Age: Early Jurassic to Late Jurassic, 145 to 202 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. 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 Old Tappan reaches New York Harbor and the Atlantic Ocean by way of the Hackensack: about 35 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Old Tappan; river miles along the main stem, rounded.
Old Tappan has a humid subtropical climate. Summer afternoons average 87° in July; winter nights fall to about 26° in January. About 46 inches of rain fall in a normal year.
On November 14 Old Tappan normally reaches 56° and falls to 39°. The record high is 72°, in 1973; the record low 18°, in 1986. The most rain on this date, 0.96 in, fell in 1979.
Normals 1991–2020 and records since 1969 at Teterboro Airport, 11 miles south-southwest. NOAA, through RCC-ACIS.
