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.
Sunny
Mostly sunny; warmer
Mostly sunny
Mostly sunny
Partly cloudy
Partly cloudy
Partly cloudy
75° on Nov. 11, 2022, the hottest reading for this week of the year since 1945. Next is 71° in 1964.
Troy’s center stands about 880 ft above sea level. Within three miles the land runs from 810 ft to 1,030 ft, a difference of 220 ft: rolling country.
Under the town center the state geologic map shows Maquoketa Formation (shale, dolostone), from the Ordovician, 445 to 487 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 59×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Dolostone. Age: Silurian, 422 to 445 million years old. About 9 mi of the line.
Shale, dolostone. Age: Ordovician, 445 to 487 million years old. About 9 mi of the line.
Dolostone. Age: Ordovician, 445 to 487 million years old. About 5 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 Honey Creek, Sugar Creek, the Fox River, the Illinois and the Mississippi: about 1,590 river miles.
Lakes on the way: Peoria Lake and Fox Lake.
1,190 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 hot-summer humid continental climate. Summer afternoons average 86° in July; winter nights fall to about 15° in January. A normal year brings about 40 inches of snow; with the rain, that comes to about 37 inches of water.
On November 14 Troy normally reaches 48° and falls to 31°. The record high is 70°, in 1971; the record low 8°, in 1959. The most rain on this date, 1.13 in, fell in 1957.
Normals 1991–2020 and records since 1945 at Lake Geneva Wwtp, 12 miles south. NOAA, through RCC-ACIS.
