The Arivaca 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
Sunny
Mostly sunny
Chance of showers
Mostly sunny
Sunny
Sunny
90° on Nov. 14, 2017, the hottest reading for this week of the year since 1959. Next is 89° in 1999.
Arivaca’s center stands about 3,630 ft above sea level. Within three miles the land runs from 3,560 ft to 4,230 ft, a difference of 670 ft: hilly country. The highest named summit within 15 miles is Atascosa Peak, about 6,360 ft, 15 miles southeast.
Under the town center the state geologic map shows Pliocene to middle Miocene deposits (conglomerate, sandstone), from the Early Miocene to Pleistocene, 2 to 16 million years old.
The section below crosses 6 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 10×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Conglomerate, sandstone. Age: Early Miocene to Pleistocene, 2 to 16 million years old. About 7 mi of the line.
Arenite, conglomerate. Age: Late Jurassic to Late Cretaceous, 80 to 160 million years old. About 6 mi of the line.
Diorite, alkali-granite, granodiorite. Age: Early Jurassic to Late Jurassic, 150 to 180 million years old. About 3 mi of the line.
Gravel, sand. Age: Late Pliocene to Pleistocene, 0.8 to 3 million years old. About 3 mi of the line.
Hypabyssal-dacite, mafic-volcanic, hypabyssal-rhyolite. Age: Late Eocene to Middle Miocene, 14 to 35 million years old. About 2 mi of the line.
Rhyolite, sandstone, conglomerate. Age: Early Jurassic to Late Jurassic, 160 to 200 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.
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.
Arivaca has a hot semi-arid climate. Summer afternoons average 97° in June; winter nights fall to about 35° in December. About 14 inches of rain fall in a normal year.
On November 14 Arivaca normally reaches 75° and falls to 42°. The record high is 90°, in 2017; the record low 27°, in 1961. The most rain on this date, 0.83 in, fell in 1959.
Normals 1991–2020 and records since 1959 at Sasabe, 14 miles west-southwest. NOAA, through RCC-ACIS.
