Unnamed Thermal Spring

Lake County, California · Near Cobb
38.7770°N, 122.7630°W · 2,170 ft
120°F 67°F air · Good soaking weather 2,170 ft Short Walk Camping nearby (13.4 mi)
Aerial view of the ground around the spring LiDAR bare-earth view of the same ground around the spring
Aerial LiDAR bare earth

Drag the handle to compare the two views. The orange dot marks the spring, in a frame about three quarters of a mile wide.

Near Cobb in Lake County, a few miles out, an unnamed hot spring with a recorded temperature of 120 degrees. Hot enough that stepping straight in from the source would be too much for most people. Big Sulphur Creek Road runs close by. The record has no landowner and no word on public access.

Location

The record puts the spring about three hundred feet off Big Sulphur Creek Road, an easy short walk. It sits a little over two thousand feet up. This is a wet corner of the county going by the climate on file, thirty-four inches a year, though snow barely registers, a couple of inches.

Winter carries the recommendation on file. Warm Springs Rec Area, thirteen or so miles away, is the campground listed. At 120 degrees the water can burn; ease in and check how hot it is where you plan to sit. Access is not recorded, so find out first. The record is blank on fees.

Terrain

Aircraft with laser scanners measured this ground to within inches. The scan strips out trees and buildings, leaving the bare shape of the land around this spring.

Setting
Canyon floor
Steep ground climbs away on both sides of the spring.
Highest ground nearby
519 ft above the spring
Within a quarter mile, to the east
Cross-section through the spring

A slice through the ground from west to east, about 0.6 miles end to end.

Elevation data: USGS 3D Elevation Program. Aerial imagery: USGS The National Map. Public domain.

Heat Below
186 milliwatts per square meter of heat flow

That's about 3 times the US average of 65. It's higher than at 99% of the springs on this site.

Heat flow measures the warmth working its way up through the ground from deep inside the earth. Where it runs high, rain and snowmelt that seep down through cracks in the rock come back up hot.

Heat flow estimate: Stanford Thermal Earth Model (Aljubran & Horne, 2024), CC BY 4.0.

Monthly Climate
45°
Jan
47°
Feb
48°
Mar
53°
Apr
59°
May
69°
Jun
73°
Jul
73°
Aug
69°
Sep
62°
Oct
51°
Nov
45°
Dec
Annual Precip: 34.4 in Annual Snow: 2.0 in
Best Time to Visit
January Air 45°F · Water 120°F · +75° contrast
December Air 45°F · Water 120°F · +75° contrast
February Air 47°F · Water 120°F · +73° contrast
January offers 28°F more contrast than August
Current Conditions
67°F
NNE 3.6 mph 36% Good soaking weather
Tuesday 80° Low 62° Sunny
Spring is +40° warmer
Wednesday 72° Low 56° Sunny
Spring is +48° warmer
Thursday 75° Low 55° Sunny 2% precip
Spring is +45° warmer
Friday 81° Low 59° Sunny
Spring is +39° warmer
Saturday 81° Low 63° Sunny
Spring is +39° warmer
Nearby Camping
Nearby Camping
Warm Springs Rec Area 13.4 mi away

Overview Warm Springs Recreation Area is a day-use park located at Lake Sonoma, which is just a 45 minute drive north of Santa Rosa and a 2 hour trip from San Francisco. There is no overnight camping available at this facility World famous vineyards and a land rich in history surround the lake, where visitors enjoy boating, fishing and exploring the area's extensive trail network.Recreation The Woodland Ridge Nature Trail begins at the park and winds up the ridge, rewarding hikers with great...

Reservable Yes
Reserve on Recreation.gov →
Temperature
120°F
Warm Hot Boiling
Water Temp 120°F (49°C)
Avg Air Temp 58°F
Above Ambient +62°F
Great soaking conditions September
Access
Road Access Short Walk
Nearest Road Big Sulphur Creek Road
Distance to Road 328 ft
Frequently Asked Questions
What is the water temperature at ?
has a water temperature of 120°F (49°C). This is considered a hot spring, well above body temperature.
Where is located?
is located in Lake County, California at 2,170 feet elevation, near Cobb. Coordinates: 38.7770°N, 122.7630°W.
How do I get to ?
has Short Walk road access, with the nearest road being Big Sulphur Creek Road (328 ft from the road).
Can I camp near ?
Yes, Warm Springs Rec Area is located nearby (13.4 miles away).
Is it safe to soak at ?
With care. At 120°F is hot enough to need short sessions, fifteen to twenty minutes, and plenty of water. Enter slowly and get out if you feel light-headed.