The Perth 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
Sunny; warmer
Partly cloudy
Mostly cloudy
Chance of showers; cooler
Mostly cloudy
Chance of showers
−20° on Nov. 11, 1986, the coldest reading for this week of the year since 1945. Next is −18° in 1959.
Perth’s center stands about 1,720 ft above sea level. Within three miles the land runs from 1,660 ft to 1,760 ft, a difference of 100 ft: gently rolling country.
Under the town center the state geologic map shows Pierre Formation (shale), from the Late Cretaceous, 66 to 100 million years old.
The section below crosses 2 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 54×. 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 23 mi of the line.
Shale, sandstone. Age: Late Cretaceous, 66 to 100 million years old. About 2 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 Perth reaches Devils Lake by way of Lake Alice and Lake Irvine: about 85 river miles. Devils Lake has no outlet to the sea: the water leaves only by evaporating or soaking into the ground.
Lakes on the way: Lake Irvine and Lake Alice.
Often dry. About 40% of the way is mapped as streams that run only after rain or snowmelt; the water makes the whole trip in floods.
No outlet, mostly. Devils Lake has spilled toward the Sheyenne River only at its highest stands.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Perth; river miles along the main stem, rounded.
Perth has a warm-summer humid continental climate. Summer afternoons average 79° in July; winter nights fall to about −5° in January. About 20 inches of rain fall in a normal year.
On November 14 Perth normally reaches 36° and falls to 16°. The record high is 63°, in 1953; the record low −18°, in 1959. The most rain on this date, 0.12 in, fell in 1960.
Normals 1991–2020 and records since 1945 at Belcourt Keya Radio, 16 miles west-northwest, 240 ft higher. NOAA, through RCC-ACIS.
