The North San Ysidro 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.
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−4° on Nov. 13, 2018, the coldest reading for this week of the year since 1916. Next is −3° in 2014.
North San Ysidro’s center stands about 6,530 ft above sea level. Within three miles the land runs from 6,290 ft to 7,570 ft, a difference of 1,280 ft: steep hill country. The highest named summit within 15 miles is Barillas Peak, about 9,360 ft, 8 miles north-northeast.
Under the town center the state geologic map shows Pennsylvanian rocks, undivided (shale, limestone, mixed-clastic), from the Carboniferous, 299 to 324 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 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.
Shale, limestone, mixed-clastic. Age: Carboniferous, 299 to 324 million years old. About 12 mi of the line.
Sandstone. Age: Permian, 273 to 290 million years old. About 7 mi of the line.
Sandstone, limestone, dolostone. Age: Carboniferous to Permian, 252 to 324 million years old. About 2 mi of the line.
Plutonic. Age: Paleoproterozoic to Mesoproterozoic, 1 to 2.5 billion years old. About 2 mi of the line.
Sandstone, carbonate, evaporite. Age: Permian, 273 to 290 million years old. About 0.4 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 North San Ysidro reaches the Gulf of America by way of Cow Creek, the Pecos and the Rio Grande: about 1,500 river miles.
Lakes on the way: Paz Ramirez Lake, Amistad Reservoir, Red Bluff Reservoir and Lake McMillan.
410 miles of the trip are on the Pecos.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of North San Ysidro; river miles along the main stem, rounded.
North San Ysidro has a oceanic climate. Summer afternoons average 85° in July; winter nights fall to about 18° in January. A normal year brings about 26 inches of snow; with the rain, that comes to about 16 inches of water.
On November 14 North San Ysidro normally reaches 55° and falls to 26°. The record high is 74°, in 1949; the record low 1°, in 1940. The most rain on this date, 0.80 in, fell in 1997.
Normals 1991–2020 and records since 1916 at Pecos National Monument, 9 miles northwest, 350 ft higher. NOAA, through RCC-ACIS.
