The Rockwall 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 cloudy
Showers likely; cooler
Chance of showers; warmer
Partly cloudy
Partly cloudy
Partly cloudy
Mostly sunny
87° on Nov. 15, 2025, the hottest reading for this week of the year since 1946. Next is 84° in 2013.
Rockwall’s center stands about 590 ft above sea level. Within three miles the land runs from 420 ft to 600 ft, a difference of 180 ft: gently rolling country.
Under the town center the state geologic map shows Marlbrook Marl (clay), from the Late Cretaceous, 66 to 72 million years old.
The section below crosses 5 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. Age: Late Cretaceous, 66 to 72 million years old. About 10 mi of the line.
Sandstone-mudstone. Age: Late Cretaceous, 66 to 72 million years old. About 4 mi of the line.
Limestone, carbonate. Age: Late Cretaceous, 66 to 72 million years old. About 3 mi of the line.
Fine-detrital, coarse-detrital. Age: Holocene, less than 12,000 years old. About 2 mi of the line.
Sand. Age: Pleistocene to Holocene, less than 2.6 million years old. About 2 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 Rockwall reaches Galveston Bay and the Gulf of America by way of Buffalo Creek, the East Fork Trinity and the Trinity: about 450 river miles.
Lake on the way: Woodlands Golf Course Lake.
220 miles of the trip are on the Trinity.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Rockwall; river miles along the main stem, rounded.
Rockwall has a humid subtropical climate. Summer afternoons average 95° in August; winter nights fall to about 36° in January. About 42 inches of rain fall in a normal year.
Normals 1991–2020 and records since 1946 at Richardson, 17 miles west-northwest. NOAA, through RCC-ACIS.
