The Troy 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
Partly cloudy
Partly cloudy
Showers likely
75° on Nov. 14, 1999, the hottest reading for this week of the year since 1877. Next is 72° in 1949.
Troy’s center stands about 1,700 ft above sea level. Within three miles the land runs from 1,620 ft to 1,740 ft, a difference of 120 ft: gently rolling country. The highest named summit within 15 miles is Stony Point, about 1,970 ft, 14 miles east-northeast.
Under the town center the state geologic map shows Sioux Quartzite (quartzite, mudstone), from the Paleoproterozoic, 1.6 to 2 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 56×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Quartzite, mudstone. Age: Paleoproterozoic, 1.6 to 2 billion years old. About 15 mi of the line.
Conglomerate, sandstone, mudstone. Age: Late Cretaceous, 72 to 100 million years old. About 6 mi of the line.
Chert, shale, chalk. Age: Early Cretaceous to Late Cretaceous, 66 to 145 million years old. About 3 mi of the line.
Quartzite. Age: Paleoproterozoic, 1.6 to 2.5 billion 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.
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 Troy reaches the Gulf of America by way of North Branch Pipestone Creek, Pipestone Creek, Split Rock Creek, the Big Sioux, the Missouri and the Mississippi: about 2,110 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 Troy; river miles along the main stem, rounded.
Troy has a warm-summer humid continental climate. Summer afternoons average 82° in July; winter nights fall to about 5° in January. A normal year brings about 40 inches of snow; with the rain, that comes to about 29 inches of water.
On November 14 Troy normally reaches 42° and falls to 23°. The record high is 75°, in 1999; the record low −12°, in 1959. The most rain on this date, 0.38 in, fell in 2024.
Normals 1991–2020 and records since 1877 at Pipestone, 5 miles southeast. NOAA, through RCC-ACIS.
