San Antonio Warm Spring Look only

San Antonio Warm Spring reads 101°F at the source (NCEI, historical reading). Managed by Valles Caldera National Preserve (checked 2026-08-19).

Cool Warm Hot Boiling-class 101°F

101°F / 38°C

Warm range at the source — bath-warm

Reading from the NCEI Thermal Springs List (historical reading, 1981 compilation). Source temperature — lower pools usually run cooler.

Water temperatures change with flow and season — test before entering, and never submerge your head in warm natural water. CDC guidance on Naegleria fowleri.

The rule here

This is a thermal feature to see, not a place to get in the water. Valles Caldera National Preserve puts it this way:

“No swimming or bathing is permitted in Park waters.”

Valles Caldera National Preserve, checked 2026-08-19

Worth knowing: The NCEI coordinate falls inside Valles Caldera National Preserve, which the National Park Service added in April 2021 to the list of park units with significant thermal features under the Geothermal Steam Act. The preserve’s superintendent’s compendium rule above applies to all park waters.

Nearby springs

Identity, coordinates, and temperature quoted from the NCEI Thermal Springs List (historical reading, 1981 compilation).