The Rockville 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
Partly cloudy
Partly cloudy
Showers likely; cooler
Partly cloudy
Showers likely
Chance of showers
90° on Nov. 14, 1999, the hottest reading for this week of the year since 1904. Next is 81° in 1990.
Rockville’s center stands about 3,750 ft above sea level. Within three miles the land runs from 3,680 ft to 6,030 ft, a difference of 2,350 ft: mountain country. The highest named summit within 15 miles is Clear Creek Mountain, about 8,120 ft, 14 miles northeast.
The section below crosses 6 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 5×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Arenite, sandstone-mudstone. Age: Early Jurassic to Middle Jurassic, 164 to 202 million years old. About 12 mi of the line.
Unconsolidated. Age: Quaternary, less than 2.6 million years old. About 6 mi of the line.
Mudstone. Age: Late Triassic, 202 to 237 million years old. About 5 mi of the line.
Conglomerate, sandstone. Age: Late Triassic, 210 to 230 million years old. About 0.6 mi of the line.
Mudstone. Age: Late Triassic, 210 to 230 million years old. About 0.4 mi of the line.
Siltstone-mudstone. Age: Early Triassic, 247 to 252 million 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 Rockville reaches the Gulf of California by way of the Virgin and the Colorado: about 620 river miles.
Lakes on the way: Lake Mead, Lake Mohave and Lake Havasu.
290 miles of the trip are on the Colorado.
Seldom reaches the sea. Dams and canals now take nearly all of the Colorado before its old delta in Mexico.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Rockville; river miles along the main stem, rounded.
Rockville has a cold semi-arid climate. Summer afternoons average 100° in July; winter nights fall to about 29° in December. About 16 inches of rain fall in a normal year, with about 4 inches of snow.
On November 14 Rockville normally reaches 65° and falls to 38°. The record high is 90°, in 1999; the record low 14°, in 1916. The most rain on this date, 0.92 in, fell in 1955.
Normals 1991–2020 and records since 1904 at Zion National Park, 5 miles northeast, 290 ft higher. NOAA, through RCC-ACIS.
