The Tappen 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.
Sunny
Mostly sunny
Mostly sunny
Mostly cloudy
Chance of showers
Partly cloudy; cooler
Showers likely
71° on Nov. 14, 2025, the hottest reading for this week of the year since 1987. Next is 69° in 2001.
Tappen’s center stands about 1,770 ft above sea level. Within three miles the land runs from 1,730 ft to 1,840 ft, a difference of 110 ft: gently rolling country. The highest named summit within 15 miles is McPhail Butte, about 1,920 ft, 7 miles north.
Under the town center the state geologic map shows Pierre Formation (shale), from the Late Cretaceous, 66 to 100 million years old.
The section below crosses 3 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 45×. 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, sandstone. Age: Late Cretaceous, 66 to 100 million years old. About 14 mi of the line.
Shale. Age: Late Cretaceous, 66 to 100 million years old. About 10 mi of the line.
Sandstone, siltstone, claystone. Age: Late Cretaceous, 66 to 100 million years old. About 0.8 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.
Tappen has a warm-summer humid continental climate. Summer afternoons average 80° in July; winter nights fall to about 1° in January. A normal year brings about 49 inches of snow; with the rain, that comes to about 20 inches of water.
On November 14 Tappen normally reaches 39° and falls to 20°. The record high is 71°, in 2025; the record low −5°, in 2014. The most rain on this date, 0.15 in, fell in 1997.
Normals 1991–2020 and records since 1987 at Streeter 5 NW, 14 miles southeast, 190 ft higher. NOAA, through RCC-ACIS.
