Sulphur Bank

Lake County, California · Near Clearlake Oaks
39.0020°N, 122.6640°W · 1,369 ft
156°F 62°F air · Good soaking weather 1,369 ft Short Walk Camping nearby (20.2 mi)
Very Hot Source, Use Extreme Caution

At 156°F, the source water at Sulphur Bank is hot enough to cause burns. Some hot springs this hot have cooler side pools or downstream areas suitable for soaking. Always test the water temperature before entering.

Sulphur Bank is a scalding thermal site in Lake County, a mile or so from Clearlake Oaks. The water here is far too hot to touch, well past anything a person could sit in. This is a place to look at, if it can be visited at all. Ownership and public access are both blank in the record.

Location
16 miles from Clearlake Oaks, CA

Low elevation, under 1,400 feet, mild year round, rain mostly in winter and only a dusting of snow. About a fifth of a mile separates it from the closest road, which is not named in the record. No land owner or unit is attached. The nearest campground on file is Little Stony, twenty miles off.

Winter is the listed season and the ground stays mostly clear of snow. Short walk from the road. Do not go in the water. At this temperature it will burn skin on contact. Nobody has logged access or an owner, and no fee either, so find out who controls the land before you make the trip. Camping is a long way off at Little Stony.

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 Sulphur Bank.

Aerial view of the ground around Sulphur Bank LiDAR bare-earth view of the same ground around Sulphur Bank
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.

Setting
Hillside
The spring sits on a steep slope that climbs to the south.
Highest ground nearby
284 ft above the spring
Within a quarter mile, to the south
Cross-section through the spring

A slice through the ground from south to north, about 0.6 miles end to end.

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

Heat Below
191 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
47°
Jan
48°
Feb
51°
Mar
57°
Apr
63°
May
72°
Jun
78°
Jul
78°
Aug
73°
Sep
64°
Oct
53°
Nov
46°
Dec
Annual Precip: 25.4 in Annual Snow: 4.7 in
Best Time to Visit
December Air 46°F · Water 156°F · +110° contrast
January Air 47°F · Water 156°F · +109° contrast
February Air 48°F · Water 156°F · +108° contrast
December offers 32°F more contrast than August
Current Conditions
62°F
WSW 10.8 mph 51% Good soaking weather
Tuesday 83° Low 61° Sunny
Spring is +73° warmer
Wednesday 76° Low 59° Sunny 5% precip
Spring is +80° warmer
Thursday 77° Low 58° Sunny
Spring is +79° warmer
Friday 83° Low 60° Sunny
Spring is +73° warmer
Saturday 84° Low 62° Sunny
Spring is +72° warmer
Where to Stay

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Nearby Camping
Little Stony 20.2 mi away

Overview This location is available on a first-come, first-served basis only. Visitors are required to physically arrive at the campground to purchase and claim a site.Once on-site, you are able to pay for your campsite(s) by scanning a QR code using the Recreation.gov mobile app, and the Scan and Pay feature.In order to utilize Scan & Pay on site, you will need to first download the free Recreation.gov mobile app https://www.recreation.gov/mobile-app prior to your arrival as some remote area...

Reservable Yes
Reserve on Recreation.gov →
Temperature
156°F
Warm Hot Boiling
Water Temp 156°F (69°C)
Avg Air Temp 61°F
Above Ambient +95°F
Great soaking conditions September
Access
Road Access Short Walk
Distance to Road 0.2 mi
Frequently Asked Questions
What is the water temperature at Sulphur Bank?
Sulphur Bank has a water temperature of 156°F (69°C). This is considered a hot spring, well above body temperature.
Where is Sulphur Bank located?
Sulphur Bank is located in Lake County, California at 1,369 feet elevation, near Clearlake Oaks. Coordinates: 39.0020°N, 122.6640°W.
How do I get to Sulphur Bank?
Sulphur Bank has Short Walk road access (0.2 mi from the road).
Can I camp near Sulphur Bank?
Yes, Little Stony is located nearby (20.2 miles away).
Is it safe to soak at Sulphur Bank?
No, not at the source. The water at Sulphur Bank reaches 156°F, which can cause severe burns within seconds. Look for cooled side pools or downstream stretches, and test with a hand before anything else.