File:South elevation. Camera facing north - Warner Ranch, Barn-Trading Post, San Felipe Road (State Highway S2), Warner Springs, San Diego County, CA HABS CAL,37-WARN.V,1B-5.tif — public domain
Warner Hot Springs reaches 138°F in the mountains northeast of San Diego, among California's hottest documented springs. Sitting at 3,170 feet with a sodium-sulfate composition of 355 mg/L TDS, it represents significant geothermal potential just 11 feet from the road.
The spring emerges near the Pacific Crest Trail in terrain where coastal maritime influence meets desert climate patterns. At a roadside location near Julian, it flows through chaparral vegetation with manzanita and chamise typical of the southern California backcountry, creating a surprising thermal contrast in mountain terrain.
History of Warner Hot Spring
Waters here are heated by circulation through deep faults in the Peninsular Ranges geology, where Precambrian crystalline basement rocks and younger plutonic intrusions provide the heat source. The sodium-sulfate signature indicates long residence time at depth, where thermal alteration of silicate minerals enriches the water chemistry.
The spring sits practically at road level with just 11 feet of access, making it among California's most convenient geothermal destinations. Indian Flats Campground, 7.7 km away, offers basic camping near the Pacific Crest Trail, though it closes seasonally for Arroyo toad breeding protection.
Is Warner Hot Spring worth visiting?
Best for
- Hot spring soaking
- Easy day trips
- Overnight camping trips
Warner Hot Spring offers an accessible hot spring experience — great for a day trip.
Annual Precip: 13.8 in
Annual Snow: 7.2 in
December
Air 49°F · Water 138°F · +89° contrast
January
Air 50°F · Water 138°F · +88° contrast
February
Air 51°F · Water 138°F · +87° contrast
December offers 31°F more contrast than August
Recent Temperature
124.0°F
(51.1°C)
Measured Nov 20, 1963
The water at Warner Hot Spring is slightly acidic (pH 6.6) with 355 mg/L total dissolved solids.
pH influences mineral absorption through skin
Higher mineral concentration for therapeutic soaking
May support bone density and joint health
Known for muscle relaxation and stress relief
Supports circulation and skin hydration
Traditionally used for skin conditions and inflammation
Natural antiseptic with skin health benefits
17 sites. Pacific Crest Trail Access. No Water. The nearest water can be found at the Warner Springs Gas Station. Indian Flats will be temporarily closed for Arroyo Toad protection during breeding season beginning April 1st through at least May 31st.
Reserve on Recreation.gov →
Swimsuit & towel
Water bottle
Stay hydrated, especially in hot water
Camping gear
Nearby camping at Indian Flats Campground
Trash bag
Pack out what you pack in
Water shoes
Hot ground near source
USGS Quad: WARNER SPRINGS 7.5 · PP 492: 179.0 · NOAA: 7.0 · AMS Map: SANTA ANA
What is the water temperature at Warner Hot Spring?
Warner Hot Spring has a water temperature of 138°F (59°C). This is considered a hot spring, well above body temperature.
Where is Warner Hot Spring located?
Warner Hot Spring is located in San Diego County, California at 3,170 feet elevation, near Julian. Coordinates: 33.2840°N, 116.6310°W.
How do I get to Warner Hot Spring?
Warner Hot Spring has Roadside road access (11 ft from the road).
Can I camp near Warner Hot Spring?
Yes, Indian Flats Campground is located nearby (4.8 miles away).
What minerals are in the water at Warner Hot Spring?
Water chemistry analysis shows the presence of pH, Total Dissolved Solids, Calcium, Magnesium, Sodium, Sulfate, Chloride. The pH is 6.6 (slightly acidic). Total dissolved solids measure 355 mg/L.
Is it safe to soak at Warner Hot Spring?
At 138°F, Warner Hot Spring is hot enough to require caution. Enter slowly, limit soaking sessions to 15–20 minutes, and stay hydrated. Access may be on private land or unconfirmed — verify current conditions before visiting. Always tell someone your plans before visiting remote hot springs.
Is Warner Hot Spring crowded?
Warner Hot 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 Warner Hot Spring?
Essentials for Warner Hot Spring: swimsuit, towel, water bottle, camping gear, a trash bag to pack out what you pack in. The water is over 110°F — test the temperature before entering and watch for scalding near the source.