The Union 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
Sunny
Sunny
Sunny
Sunny
Mostly sunny
Mostly sunny
15° on Nov. 15, 1969, the coldest reading for this week of the year since 1949. Next is 19° in 2013.
Union’s center stands about 630 ft above sea level. Within three miles the land runs from 480 ft to 670 ft, a difference of 190 ft: gently rolling country.
Under the town center the state geologic map shows Granite - Bald Rock pluton, from the Carboniferous to Permian, 252 to 359 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 48×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Granite. Age: Carboniferous to Permian, 252 to 359 million years old. About 10 mi of the line.
Metadiorite. Age: Neoproterozoic to Ordovician, 445 to 1,000 million years old. About 6 mi of the line.
Metavolcanic. Age: Neoproterozoic, 542 to 1,000 million years old. About 4 mi of the line.
Metagranite, metadiorite. Age: Neoproterozoic to Cambrian, 487 to 1,000 million years old. About 2 mi of the line.
Metadiorite. Age: Neoproterozoic to Ordovician, 445 to 1,000 million years old. About 2 mi of the line.
Metavolcanic. Age: Neoproterozoic, 542 to 1,000 million years old. About 0.3 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 Union reaches the Atlantic Ocean by way of Shoal Creek, Fairforest Creek, the Tyger, the Broad, the Congaree, the Santee and the South Santee: about 250 river miles.
Lake on the way: Lib Pines Lake.
70 miles of the trip are on the Santee.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Union; river miles along the main stem, rounded.
Union has a humid subtropical climate. Summer afternoons average 90° in July; winter nights fall to about 29° in January. About 45 inches of rain fall in a normal year, with about 2 inches of snow.
On November 14 Union normally reaches 64° and falls to 37°. The record high is 82°, in 1964; the record low 19°, in 2013. The most rain on this date, 1.16 in, fell in 1972.
Normals 1991–2020 and records since 1949 at Union 8 S, 8 miles south-southwest, 180 ft lower. NOAA, through RCC-ACIS.
