The Dorchester 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
Showers likely; cooler
Chance of showers; warmer
Sunny
Mostly cloudy
Partly cloudy
Partly cloudy
8.22 inches of rain fell in two days, the most for this week of the year since records began in 1897. The next wettest, 6.03 inches, fell in 1978.
Dorchester’s center stands about 870 ft above sea level. Within three miles the land runs from 740 ft to 880 ft, a difference of 140 ft: gently rolling country.
Under the town center the state geologic map shows Austin Chalk (marlstone, chalk), from the Late Cretaceous, 66 to 100 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.
Marlstone, chalk. Age: Late Cretaceous, 66 to 100 million years old. About 14 mi of the line.
Black-shale, siltstone. Age: Late Cretaceous, 66 to 100 million years old. About 10 mi of the line.
Sandstone-mudstone. Age: Late Cretaceous, 66 to 100 million years old. About 1 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 Dorchester reaches Galveston Bay and the Gulf of America by way of the East Fork Trinity and the Trinity: about 510 river miles.
Lakes on the way: Woodlands Golf Course Lake, Lavon Lake and Corder 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 Dorchester; river miles along the main stem, rounded.
Dorchester has a humid subtropical climate. Summer afternoons average 93° in July; winter nights fall to about 34° in January. About 44 inches of rain fall in a normal year.
On November 14 Dorchester normally reaches 64° and falls to 44°. The record high is 86°, in 1955; the record low 21°, in 1940. The most rain on this date, 7.93 in, fell in 1994.
Normals 1991–2020 and records since 1897 at Sherman, 12 miles north-northeast, 110 ft lower. NOAA, through RCC-ACIS.
