The Allen 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 sunny
Mostly sunny
Mostly sunny
Partly cloudy
Partly cloudy
Partly cloudy
Showers likely
79° on Nov. 14, 2025, the hottest reading for this week of the year since 1957. Next is 75° in 1971.
Allen’s center stands about 1,520 ft above sea level. Within three miles the land runs from 1,320 ft to 1,590 ft, a difference of 270 ft: rolling country.
Under the town center the state geologic map shows Carlile Shale, from the Late Cretaceous, 66 to 100 million years old.
The section below crosses 4 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 43×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Shale. Age: Late Cretaceous, 66 to 100 million years old. About 20 mi of the line.
Limestone, shale. Age: Late Cretaceous, 66 to 100 million years old. About 2 mi of the line.
Sandstone, shale. Age: Early Cretaceous, 100 to 145 million years old. About 2 mi of the line.
Shale, limestone. Age: Late Cretaceous, 66 to 100 million years old. About 0.9 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 Allen reaches the Gulf of America by way of South Creek, Aowa Creek, the Missouri and the Mississippi: about 1,930 river miles.
1,170 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Allen; river miles along the main stem, rounded.
Allen has a hot-summer humid continental climate. Summer afternoons average 85° in July; winter nights fall to about 9° in January. About 29 inches of rain fall in a normal year.
On November 14 Allen normally reaches 48° and falls to 25°. The record high is 79°, in 2025; the record low −19°, in 1959. The most rain on this date, 0.28 in, fell in 2008.
Normals 1991–2020 and records since 1957 at Concord, 8 miles west-southwest. NOAA, through RCC-ACIS.
