Unnamed Thermal Spring
This 108-degree spring emerges just 19 meters from a paved road in San Luis Obispo County, creating waters that exceed ambient temperatures by 46 degrees in the heart of California wine country.
Standing at 675 feet elevation near Paso Robles, you encounter one of the state's hottest roadside thermal springs. The landscape transitions from rolling vineyards to oak-studded foothills. The water runs hot enough to produce visible steam in cool weather, emerging clear and vigorously from the earth. Nearby grasslands glow golden under the California sun.
This spring's exceptional heat reflects deep geothermal activity in the region, where Pacific plate tectonics and crustal heating create thermal gradients. The warm waters have attracted human use for generations, from Native American settlement through modern recreation and agriculture.
The spring requires only a few steps from a roadside pullout, making it accessible to anyone. Water temperature demands respect—it approaches boiling and will scald flesh. Visit during cooler months when steaming pools create dramatic displays. Year-round access is available.
Is this spring worth visiting?
Best for
- Hot spring soaking
- Easy day trips
- Overnight camping trips
Overview Cerro Alto Campground is a well-known hiking and mountain biking paradise. It is located a short distance from the sandy beaches of Morro Bay, where visitors enjoy surfing, fishing, kayaking, sailing, scuba diving and more. While the campground offers a serene, relaxed environment, both Morro Bay and the nearby town of Atascadero offer numerous dining opportunities, shopping, museums and other activities. Wine Tasting in the Tempelton, Paso Robles Area is also a very popular experi...