The Irvine 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.
26° on Nov. 12, 1938, the coldest reading for this week of the year since 1906. Next is 30° in 1919.
Irvine’s center stands about 60 ft above sea level. Within three miles the land runs from 10 ft to 470 ft, a difference of 460 ft: hilly country. The highest named summit within 15 miles is Flores Peak, about 1,800 ft, 12 miles east-northeast.
Under the town center the state geologic map shows Quaternary alluvium and marine deposits (coarse-detrital), from the Pleistocene to Holocene, less than 2.6 million years old.
The section below crosses 7 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 11×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Coarse-detrital. Age: Pleistocene to Holocene, less than 2.6 million years old. About 8 mi of the line.
Coarse-detrital. Age: Pleistocene, less than 2.6 million years old. About 5 mi of the line.
Sandstone, conglomerate. Age: Middle Eocene to Early Miocene, 16 to 48 million years old. About 3 mi of the line.
Sandstone, siltstone-mudstone. Age: Late Cretaceous, 66 to 100 million years old. About 2 mi of the line.
Sandstone, mudstone. Age: Oligocene to Pliocene, 2.6 to 34 million years old. About 0.6 mi of the line.
Siltstone-mudstone. Age: Early Cretaceous to Late Cretaceous, 66 to 145 million years old. About 0.5 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 1 smaller unit 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 Irvine reaches the Pacific Ocean by way of San Diego Creek: about 10 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Irvine; river miles along the main stem, rounded.
Irvine has a hot semi-arid climate. Summer afternoons average 85° in August; winter nights fall to about 48° in December. About 12 inches of rain fall in a normal year.
On November 14 Irvine normally reaches 75° and falls to 53°. The record high is 100°, in 1933; the record low 30°, in 1938. The most rain on this date, 1.83 in, fell in 1946.
Normals 1991–2020 and records since 1906 at Santa Ana Fire Station, 6 miles north-northwest. NOAA, through RCC-ACIS.