File:Mamelons visible on 33 year old adult.jpg — cc by-sa 4.0
Sulphur Spring emerges at 75°F near San Francisco Bay, reaching temperatures 14.4 degrees warmer than the mild East Bay climate in a nearly roadside-accessible location.
Just 33 meters from Lonoak Road, this spring flows at minimal elevation in the low coastal hills of Contra Costa County near Waldon, offering easy access to thermal water in an urban-fringe landscape.
History of Sulphur Spring
Named for its characteristic sulfur minerals, the spring flows in a Mediterranean climate zone with minimal precipitation and virtually no winter snow, typical of the Bay Area's mild temperate conditions.
Roadside parking and immediate access make this an excellent quick visit. Visit during cooler months to avoid peak Bay Area heat. Aquatic Park Cove on San Francisco's waterfront offers nearby accommodations.
Is Sulphur Spring worth visiting?
Best for
- Easy day trips
- Overnight camping trips
Sulphur Spring is well suited for easy day trips and overnight camping trips.
Annual Precip: 16.8 in
Annual Snow: 0.1 in
January
Air 50°F · Water 75°F · +25° contrast
December
Air 50°F · Water 75°F · +25° contrast
February
Air 52°F · Water 75°F · +23° contrast
January offers 20°F more contrast than August
Overview
Aquatic Park Cove is a vibrantly urban harbor that mimics a natural anchorage and is located on the Pacific shores of one of America's great West Coast cities. San Francisco Maritime National Historical Park's Aquatic Park Cove is the small craft gateway to San Francisco.
Vessels entering Aquatic Park Cove are instructed to contact the Park's permit officer on VHF marine radio channel 83A (157.175Mhz) using the call sign "Aquatic Park NPS" followed by transmission of the vessel'...
Reserve on Recreation.gov →
Swimsuit & towel
Water bottle
Stay hydrated, especially in hot water
Camping gear
Nearby camping at Aquatic Park Cove, Black Point Overnight Anchoring, Sailing Vessels Only (Auxiliary Engine Ok)
Trash bag
Pack out what you pack in
USGS Quad: (WALNUT CREEK 7.5) · PP 492: 85.0 · NOAA: 1.0 · AMS Map: SAN FRANCISCO
What is the water temperature at Sulphur Spring?
Sulphur Spring has a water temperature of 75°F (24°C). This is a warm thermal spring.
Where is Sulphur Spring located?
Sulphur Spring is located in Contra Costa County, California at 101 feet elevation, near Waldon. Coordinates: 37.9240°N, 122.0460°W.
How do I get to Sulphur Spring?
Sulphur Spring has Roadside road access (110 ft from the road).
Can I camp near Sulphur Spring?
Yes, Aquatic Park Cove, Black Point Overnight Anchoring, Sailing Vessels Only (Auxiliary Engine Ok) is located nearby (22.1 miles away).
Is it safe to soak at Sulphur Spring?
Sulphur Spring is generally safe for soaking at its recorded temperature. Access may be on private land or unconfirmed — verify current conditions before visiting. Always tell someone your plans before visiting remote hot springs.
Is Sulphur Spring crowded?
Sulphur Spring is accessible from a paved road, making it easy to reach. Weekends and holidays may be busier — consider visiting on a weekday for a quieter experience.
What should I bring to Sulphur Spring?
Essentials for Sulphur Spring: swimsuit, towel, water bottle, camping gear, a trash bag to pack out what you pack in.