The Decatur 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.
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Mostly sunny; warmer
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82° on Nov. 16, 1958, the hottest reading for this week of the year since 1878. Next is 81° in 1985.
Decatur’s center stands about 1,020 ft above sea level. Within three miles the land runs from 900 ft to 1,080 ft, a difference of 180 ft: gently rolling country. The highest named summit within 15 miles is Stone Mountain, about 1,670 ft, 9 miles east-northeast.
Under the town center the state geologic map shows Biotitic Gneiss / Mica Schist/ Amphibolite (amphibolite, biotite-gneiss, mica-schist), from the Precambrian to Paleozoic.
The section below crosses 8 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 56×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Gneiss, mica-schist, amphibolite. Age: Precambrian to Paleozoic. About 12 mi of the line.
Amphibolite, biotite-gneiss, mica-schist. Age: Precambrian to Paleozoic. About 4 mi of the line.
Mica-schist. Age: Precambrian to Paleozoic. About 3 mi of the line.
Biotite-gneiss. Age: Precambrian to Paleozoic. About 2 mi of the line.
Biotite-gneiss. Age: Precambrian to Paleozoic. About 0.6 mi of the line.
Granite. Age: Precambrian to Paleozoic. About 0.6 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 2 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.
Decatur straddles the Eastern Continental Divide. Rain on the southeast side runs to the Atlantic Ocean; most of the rest goes to the Gulf of America.
From the center of town, a raindrop reaches the Gulf of America by way of Peavine Creek, Peachtree Creek, the Chattahoochee and the Apalachicola: about 420 river miles. One that lands on the southeast side reaches the Atlantic Ocean by way of Shoal Creek, the South River, the Ocmulgee and the Altamaha: about 420 river miles.
Lakes on the way: Walter F George Reservoir, West Point Lake and Bartletts Ferry Lake.
110 miles of the trip are on the Apalachicola.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Decatur; river miles along the main stem, rounded.
Decatur has a humid subtropical climate. Summer afternoons average 90° in July; winter nights fall to about 36° in January. About 50 inches of rain fall in a normal year, with about 2 inches of snow.
On November 14 Decatur normally reaches 64° and falls to 44°. The record high is 80°, in 1955; the record low 22°, in 1969. The most rain on this date, 1.80 in, fell in 1888.
Normals 1991–2020 and records since 1878 from the Atlanta Area threaded record (Atlanta Hartsfield-Jackson International Airport, 13 miles southwest). NOAA, through RCC-ACIS.
