The Gilroy 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
Showers likely
Showers likely
Mostly sunny
Showers likely
Showers likely
Partly cloudy
3.84 inches of rain fell in two days, the most for this week of the year since records began in 1908. The next wettest, 3.69 inches, fell in 1972.
Gilroy’s center stands about 200 ft above sea level. Within three miles the land runs from 150 ft to 1,420 ft, a difference of 1,270 ft: steep hill country. The highest named summit within 15 miles is Mount Sizer, about 3,200 ft, 15 miles north-northeast.
Under the town center the state geologic map shows Older Quaternary alluvium and marine deposits (coarse-detrital), from the Pleistocene, less than 2.6 million years old.
The section below crosses 11 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 7×. 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 6 mi of the line.
Sandstone, siltstone-mudstone. Age: Late Cretaceous, 66 to 100 million years old. About 5 mi of the line.
Coarse-detrital. Age: Pleistocene, less than 2.6 million years old. About 4 mi of the line.
Sandstone, mudstone. Age: Jurassic to Cretaceous, 66 to 202 million years old. About 2 mi of the line.
Sandstone, mudstone. Age: Oligocene to Pliocene, 2.6 to 34 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. 5 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 Gilroy reaches the Pacific Ocean by way of Miller Slough, Llagas Creek and the Pajaro: about 30 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Gilroy; river miles along the main stem, rounded.
Gilroy has a warm-summer Mediterranean climate. Summer afternoons average 74° in September; winter nights fall to about 39° in December. About 23 inches of rain fall in a normal year.
On November 14 Gilroy normally reaches 68° and falls to 43°. The record high is 82°, in 1995; the record low 27°, in 1911. The most rain on this date, 2.12 in, fell in 2025.
Normals 1991–2020 and records since 1908 at Watsonville Waterworks, 12 miles west-southwest, 100 ft lower. NOAA, through RCC-ACIS.
