The Round Rock 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.
Chance of showers
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24° on Nov. 14, 2018, the coldest reading for this week of the year since 1942. Next is 25° in 2014.
Round Rock’s center stands about 730 ft above sea level. Within three miles the land runs from 670 ft to 870 ft, a difference of 200 ft: gently rolling country. The highest named summit within 15 miles is Jess Maynard Hill, about 1,130 ft, 14 miles west-northwest.
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 38×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Limestone, dolostone. Age: Early Cretaceous, 100 to 145 million years old. About 10 mi of the line.
Marlstone, chalk. Age: Late Cretaceous, 66 to 100 million years old. About 6 mi of the line.
Siltstone-mudstone. Age: Late Cretaceous, 66 to 100 million years old. About 6 mi of the line.
Clay, limestone. Age: Late Cretaceous, 66 to 100 million years old. About 0.7 mi of the line.
Fine-detrital, coarse-detrital. Age: Holocene, less than 12,000 years old. About 0.6 mi of the line.
Sandstone, claystone. Age: Early Cretaceous, 100 to 145 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. 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.
A raindrop that lands in Round Rock reaches the Gulf of America by way of Brushy Creek, the San Gabriel, the Little River and the Brazos: about 430 river miles.
320 miles of the trip are on the Brazos.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Round Rock; river miles along the main stem, rounded.
Round Rock has a humid subtropical climate. Summer afternoons average 97° in August; winter nights fall to about 38° in January. About 36 inches of rain fall in a normal year.
On November 14 Round Rock normally reaches 72° and falls to 47°. The record high is 89°, in 2020; the record low 24°, in 2018. The most rain on this date, 0.87 in, fell in 1998.
Normals 1991–2020 and records since 1942 from the Austin-Bergstrom Airport Area threaded record (Austin-Camp Mabry, 14 miles south-southwest). NOAA, through RCC-ACIS.
