The San Marine 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.
Chance of showers
Showers likely
Chance of showers
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Partly cloudy
Partly cloudy
20° on Nov. 13, 1978, the coldest reading for this week of the year since 1893. Next is 21° in 1955.
San Marine’s center stands about 40 ft above sea level. Within three miles the land runs from 10 ft to 1,250 ft, a difference of 1,240 ft: steep hill country. Open water lies within three miles. The highest named summit within 15 miles is Cummins Peak, about 2,510 ft, 10 miles south-southeast.
Under the town center the state geologic map shows Terrace, pediment, and lag gravels (gravel, boulders, clay), from the Pleistocene to Holocene, less than 2.6 million years old.
The section below crosses 4 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 8×. 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. Age: Middle Eocene, 38 to 48 million years old. About 7 mi of the line.
Basalt. Age: Late Eocene, 34 to 38 million years old. About 3 mi of the line.
Gravel, boulders, clay. Age: Pleistocene to Holocene, less than 2.6 million years old. About 1 mi of the line.
Mudstone. Age: Middle Eocene to Late Eocene, 34 to 48 million years old. About 1 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.
Rain that falls on San Marine runs straight into the Pacific Ocean.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of San Marine; river miles along the main stem, rounded.
San Marine has a warm-summer Mediterranean climate. Summer afternoons average 64° in July; winter nights fall to about 39° in January. About 67 inches of rain fall in a normal year.
On November 14 San Marine normally reaches 54° and falls to 42°. The record high is 72°, in 1995; the record low 22°, in 1978. The most rain on this date, 2.00 in, fell in 1918.
Normals 1991–2020 and records since 1893 at Newport, 20 miles north. NOAA, through RCC-ACIS.
