Castle Rock Springs

Lake County, California · Near Cobb
38.7680°N, 122.7170°W · 2,380 ft
163°F 67°F air · Good soaking weather 2,380 ft Roadside Camping nearby (15.6 mi)
Very Hot Source, Use Extreme Caution

At 163°F, the source water at Castle Rock Springs 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.

Aerial view of the ground around Castle Rock Springs LiDAR bare-earth view of the same ground around Castle Rock Springs
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.

Castle Rock Springs, under five miles from Cobb in Lake County, puts out water far too hot to touch. Castle Spring Road passes roughly two hundred thirty feet off, so there is no hike involved. No owner and no access status on file, and no land unit, which leaves every question about who controls the ground open.

Location

Roadside at a little under twenty-four hundred feet. Winters are wet, thirty inches or so, with a handful of snow inches in a typical year and a mild yearly average in the high fifties. No agency is recorded for the ground. The campground the record finds is a fair drive off, and no fee has been logged anywhere.

The listed months are the winter ones. Warm Springs Rec Area, sixteen miles off, is the campground on record. The water scalds, so looking is the whole activity, and any pool fed by it needs testing before a toe goes in. Ownership and access are unknown; confirm before visiting. No date accompanies the temperature.

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 Castle Rock Springs.

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

A slice through the ground from northwest to southeast, about 0.6 miles end to end.

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

Heat Below
182 milliwatts per square meter of heat flow

That's about 3 times the US average of 65. It's higher than at 98% 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
46°
Feb
47°
Mar
53°
Apr
59°
May
69°
Jun
74°
Jul
74°
Aug
69°
Sep
61°
Oct
51°
Nov
44°
Dec
Annual Precip: 30.0 in Annual Snow: 5.1 in
Best Time to Visit
January Air 45°F · Water 163°F · +119° contrast
December Air 44°F · Water 163°F · +119° contrast
February Air 46°F · Water 163°F · +117° contrast
January offers 30°F more contrast than August
Current Conditions
67°F
NNW 3.6 mph 40% Good soaking weather
Tuesday 76° Low 62° Sunny
Spring is +87° warmer
Wednesday 68° Low 56° Sunny
Spring is +95° warmer
Thursday 71° Low 54° Sunny 2% precip
Spring is +92° warmer
Friday 77° Low 59° Sunny
Spring is +86° warmer
Saturday 77° Low 63° Sunny
Spring is +86° warmer
Where to Stay

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Nearby Camping
Warm Springs Rec Area 15.6 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
163°F
Warm Hot Boiling
Water Temp 163°F (73°C)
Avg Air Temp 58°F
Above Ambient +105°F
Great soaking conditions September
Access
Road Access Roadside
Nearest Road Castle Spring Road
Distance to Road 230 ft
Frequently Asked Questions
What is the water temperature at Castle Rock Springs?
Castle Rock Springs has a water temperature of 163°F (73°C). This is considered a hot spring, well above body temperature.
Where is Castle Rock Springs located?
Castle Rock Springs is located in Lake County, California at 2,380 feet elevation, near Cobb. Coordinates: 38.7680°N, 122.7170°W.
How do I get to Castle Rock Springs?
Castle Rock Springs has Roadside road access, with the nearest road being Castle Spring Road (230 ft from the road).
Can I camp near Castle Rock Springs?
Yes, Warm Springs Rec Area is located nearby (15.6 miles away).
Is it safe to soak at Castle Rock Springs?
No, not at the source. The water at Castle Rock Springs reaches 163°F, which can cause severe burns within seconds. Look for cooled side pools or downstream stretches, and test with a hand before anything else.
Sources: Wikipedia