The Rancho Mission Viejo 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
Chance of showers
Sunny
Chance of showers
Showers likely
Mostly sunny
34° on Nov. 17, 1958, the coldest reading for this week of the year since 1921. Next is 37° in 1938.
Rancho Mission Viejo’s center stands about 240 ft above sea level. Within three miles the land runs from 110 ft to 990 ft, a difference of 880 ft: hilly country. The highest named summit within 15 miles is Santiago Peak, about 5,660 ft, 14 miles north-northeast.
The section below crosses 10 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 6×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Sandstone, mudstone. Age: Oligocene to Pliocene, 2.6 to 34 million years old. About 4 mi of the line.
Felsic-volcanic, mafic-volcanic. Age: Late Jurassic to Early Cretaceous, 100 to 164 million years old. About 3 mi of the line.
Mudstone, sandstone. Age: Paleocene to Oligocene, 23 to 66 million years old. About 2 mi of the line.
Coarse-detrital. Age: Pleistocene to Holocene, less than 2.6 million years old. About 2 mi of the line.
Argillite. Age: Paleozoic to Late Jurassic, 145 to 542 million years old. About 2 mi of the line.
Sandstone, mudstone. Age: Miocene to Pleistocene, less than 23 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. 4 smaller units along the line are not listed.
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 Rancho Mission Viejo reaches the Pacific Ocean by way of San Juan Creek: about 10 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Rancho Mission Viejo; river miles along the main stem, rounded.
Rancho Mission Viejo has a cold semi-arid climate. Summer afternoons average 74° in September; winter nights fall to about 50° in January. About 9 inches of rain fall in a normal year.
On November 14 Rancho Mission Viejo normally reaches 69° and falls to 55°. The record high is 81°, in 1940; the record low 39°, in 1938. The most rain on this date, 1.11 in, fell in 1944.
Normals 1991–2020 and records since 1921 at Newport Beach Harbor, 16 miles west-northwest, 230 ft lower. NOAA, through RCC-ACIS.
