The San Fernando 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.
Partly cloudy
Chance of showers; warmer
Chance of showers; cooler
Mostly cloudy
Mostly cloudy; warmer
Partly cloudy
Partly cloudy
3.20 inches of rain fell in two days, the most for this week of the year since records began in 1892. The next wettest, 2.69 inches, fell in 2003.
San Fernando’s center stands about 260 ft above sea level. Within three miles the land runs from 140 ft to 310 ft, a difference of 170 ft: gently rolling country.
Under the town center the state geologic map shows Uvalde Gravel, from the Late Pliocene to Pleistocene, less than 3.6 million years old.
The section below crosses 5 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 51×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Clay, sandstone. Age: Miocene, 5.3 to 23 million years old. About 7 mi of the line.
Clay. Age: Oligocene, 23 to 34 million years old. About 4 mi of the line.
Gravel. Age: Late Pliocene to Pleistocene, less than 3.6 million years old. About 2 mi of the line.
Sand. Age: Pleistocene to Holocene, less than 2.6 million years old. About 2 mi of the line.
Fine-detrital, coarse-detrital. Age: Holocene, less than 12,000 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.
A raindrop that lands in San Fernando reaches the Gulf of America by way of Los Olmos Creek and the Rio Grande: about 240 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of San Fernando; river miles along the main stem, rounded.
San Fernando has a hot semi-arid climate. Summer afternoons average 99° in July; winter nights fall to about 45° in January. About 22 inches of rain fall in a normal year.
On November 14 San Fernando normally reaches 79° and falls to 55°. The record high is 94°, in 1985; the record low 27°, in 2018. The most rain on this date, 0.56 in, fell in 1998.
Normals 1991–2020 and records since 1892 at Rio Grande City, 2 miles southeast. NOAA, through RCC-ACIS.
