The Sullivan's Island 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; warmer
Partly cloudy
Mostly sunny
Mostly sunny
Mostly sunny
Partly cloudy
84° on Nov. 12, 1989, the hottest reading for this week of the year since 1951. Next is 83° in 1964.
Sullivan's Island’s center stands barely above sea level. Within three miles the land runs from 0 ft to 40 ft, a difference of 40 ft: nearly flat ground. Open water lies within three miles.
Under the town center the state geologic map shows Tidal Marsh (peat), from the Quaternary, less than 2.6 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 64×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Clay, sand. Age: Pleistocene, less than 2.6 million years old. About 9 mi of the line.
Peat. Age: Quaternary, less than 2.6 million years old. About 3 mi of the line.
Sand, gravel. Age: Holocene, less than 12,000 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.
Rain that falls on Sullivan's Island runs straight into the Atlantic Ocean.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Sullivan's Island; river miles along the main stem, rounded.
Sullivan's Island has a humid subtropical climate. Summer afternoons average 91° in July; winter nights fall to about 36° in January. About 52 inches of rain fall in a normal year.
On November 14 Sullivan's Island normally reaches 70° and falls to 47°. The record high is 80°, in 2005; the record low 32°, in 2019. The most rain on this date, 0.65 in, fell in 1997.
Normals 1991–2020 and records since 1951 at Sullivans Island, here. NOAA, through RCC-ACIS.
