The Onaka 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 sunny
Sunny; warmer
Mostly sunny
Mostly cloudy
Partly cloudy
Partly cloudy; cooler
Showers likely
−16° on Nov. 14, 2014, the coldest reading for this week of the year since 1893. Next is −15° in 1959.
Onaka’s center stands about 1,860 ft above sea level. Within three miles the land runs from 1,800 ft to 1,900 ft, a difference of 100 ft: gently rolling country.
Under the town center the state geologic map shows Pierre Shale (shale, bentonite), from the Late Cretaceous, 66 to 100 million years old.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 55×. 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, bentonite. Age: Late Cretaceous, 66 to 100 million years old. About 24 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.
Onaka has a warm-summer humid continental climate. Summer afternoons average 84° in July; winter nights fall to about 4° in January. A normal year brings about 44 inches of snow; with the rain, that comes to about 22 inches of water.
On November 14 Onaka normally reaches 43° and falls to 21°. The record high is 70°, in 2016; the record low −16°, in 2014. The most rain on this date, 0.61 in, fell in 1928.
Normals 1991–2020 and records since 1893 at Faulkton, 20 miles east-southeast, 280 ft lower. NOAA, through RCC-ACIS.
