The De Graff 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; warmer
Mostly sunny
Partly cloudy
Mostly cloudy
Partly cloudy
Showers likely
−12° on Nov. 12, 1966, the coldest reading for this week of the year since 1945. Next is −8° in 1959.
De Graff’s center stands about 1,060 ft above sea level. Within three miles the land runs from 1,040 ft to 1,090 ft, a difference of 50 ft: nearly flat ground.
Under the town center the state geologic map shows Leucogranite (leucocratic-granitic), from the Neoarchean, 2.5 to 2.8 billion 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 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.
Leucocratic-granitic. Age: Neoarchean, 2.5 to 2.8 billion years old. About 16 mi of the line.
Conglomerate, sandstone, mudstone. Age: Late Cretaceous, 72 to 100 million years old. About 8 mi of the line.
Age: Paleoproterozoic, 1.8 to 2 billion years old. About 0.6 mi of the line.
Orthogneiss. Age: Paleoarchean to Mesoarchean, 2.8 to 3.6 billion years old. About 0.4 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 De Graff reaches the Gulf of America by way of Mud Creek, the Chippewa, the Minnesota and the Mississippi: about 2,160 river miles.
Lake on the way: Lake Pepin.
1,750 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of De Graff; river miles along the main stem, rounded.
De Graff has a hot-summer humid continental climate. Summer afternoons average 83° in July; winter nights fall to about 1° in January. A normal year brings about 43 inches of snow; with the rain, that comes to about 28 inches of water.
On November 14 De Graff normally reaches 42° and falls to 22°. The record high is 69°, in 1990; the record low −5°, in 2014. The most rain on this date, 0.40 in, fell in 2024.
Normals 1991–2020 and records since 1945 at Benson, 8 miles west-northwest. NOAA, through RCC-ACIS.
