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Every Hot Spring

San Marcos Hot Spring

San Marcos Hot Spring is a geothermal spring in California. Water at the source is recorded at 110°F (43°C).

110°F43°C recorded at the source
Hot: most people last only minutes at the source. Look for mixing pools.

Facts

Coordinates
34.5370, -119.8790 (Google Maps, OSM)
Source temperature
110°F (43°C)
Access
Unknown
Type
Unknown
Fee
Not recorded
Clothing optional
Not recorded
Nearest town
Not recorded
Data sources
NOAA NCEI. See sources

Map

Larger marker is San Marcos Hot Spring; smaller markers are other springs within 50 miles.

Quick answers

How hot is San Marcos Hot Spring?
The hottest recorded reading at the source is 110°F (43°C). That is the outlet temperature, not a pool temperature; water cools as it flows away from the source.
Where is San Marcos Hot Spring?
San Marcos Hot Spring is in California, at coordinates 34.5370, -119.8790.
What other hot springs are near San Marcos Hot Spring?
The closest listed springs, in straight-line distance, are Hot Spring (Santa Barbara County), under 1 mi; Montecito Hot Springs, 15 mi; and Hot Springs (Santa Barbara County), 15 mi.

Before you go

  • Temperatures are measured at the source and can be far hotter than any soaking pool. Test with a hand before stepping in.
  • Access, fees, and road conditions change. Verify with the land manager or owner; "public" here reflects survey records, not a current right of entry.
  • Water in natural springs is untreated. Keep your head above water and avoid soaking with open wounds. Some springs carry Naegleria fowleri risk.
  • Pack out everything, including soap residue. Many springs have been closed because of trash and overcrowding.

Sources

Dataset last rebuilt October 11, 2026. Not yet checked on site by a person. Access, fee, clothing and closure details appear only when a source below states them. How this data is built.

Merged from

  1. NOAA NCEI Thermal Springs List (archived 2025): survey location and source temperature, public domain