Pierson Hot Springs

Blaine County, Idaho · Near Ketchum
43.9900°N, 114.8000°W · 6,900 ft
109°F 24°F air · Good soaking weather 6,900 ft Roadside Camping nearby (5.1 mi)
Aerial view of the ground around Pierson Hot Springs LiDAR bare-earth view of the same ground around Pierson Hot 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.

Thirty miles from Ketchum in Blaine County, Pierson Hot Springs sits right off Valley Road, close enough to count as roadside. The temperature is right at the top of comfortable soaking, a touch under hot. No owner or access entry exists for it in the record. Alturas Lake Picnic Area is about five miles away.

Location

High. Close to seven thousand feet, where the year runs cold on average and winters bring thirteen feet of snow. That snow is the main fact about getting here. The spring is right beside Valley Road, so once you can drive the road you can reach the water. The land manager is not on file.

The record points to winter, and the water would suit that, but the snowpack means you need to know Valley Road is open. Alturas Lake Picnic Area is the closest camping on record. There is no fee information. The chemistry comes from a 1979 sample. Check land ownership and access before you go. Neither is recorded.

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 Pierson Hot Springs.

Setting
Open ground
Flat, open ground all around.
Highest ground nearby
56 ft above the spring
Within a quarter mile, to the north
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
140 milliwatts per square meter of heat flow

That's about twice the US average of 65. It's higher than at 89% 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
21°
Jan
22°
Feb
28°
Mar
33°
Apr
41°
May
50°
Jun
62°
Jul
61°
Aug
52°
Sep
37°
Oct
25°
Nov
18°
Dec
Annual Precip: 29.1 in Annual Snow: 157.7 in
Best Time to Visit
December Air 18°F · Water 109°F · +91° contrast
January Air 21°F · Water 109°F · +88° contrast
February Air 22°F · Water 109°F · +87° contrast
December offers 44°F more contrast than July
Current Conditions
24°F
S 12.1 mph 91% Good soaking weather
Tuesday 68° Low 23° Sunny
Spring is +41° warmer
Wednesday 73° Low 29° Sunny 8% precip
Spring is +36° warmer
Thursday 67° Low 35° Chance Light Rain then Showers And Thunderstorms 84% precip
Spring is +42° warmer
Friday 66° Low 32° Mostly Sunny then Chance Light Rain 30% precip
Spring is +43° warmer
Saturday 70° Low 28° Sunny 9% precip
Spring is +39° warmer
Water Chemistry Sampled 1979-09-12

The water at Pierson Hot Springs is alkaline (pH 9.3).

pH 9.3 Alkaline
pH influences mineral absorption through skin
Calcium 3 mg/L
May support bone density and joint health
Magnesium 0 mg/L
Known for muscle relaxation and stress relief
Sodium 51 mg/L
Supports circulation and skin hydration
Sulfate 32 mg/L
Traditionally used for skin conditions and inflammation
Chloride 4 mg/L
Natural antiseptic with skin health benefits
Nearby Camping
Nearby Camping
Alturas Lake Picnic Area (Id) 5.1 mi away

Overview Alturas Area Picnic B is located along the sandy shoreline of scenic Alturas Lake, at the foot of the Sawtooth Mountain Range.Recreation The site is part of the Sawtooth National Recreation Area, where outdoor activities abound. Alturas Lake offers excellent boating, water skiing, canoeing, kayaking and fishing for bull trout and Kokanee salmon. Alturas Creek runs through the adjacent campground. The 10-mile round trip Alpine Meadows Trail begins nearby, with spectacular canyon, mea...

Reservable Yes
Reserve on Recreation.gov →
Mile-High Advisory 6,900 ft

Pierson Hot Springs sits at 6,900 feet above sea level, way above the mile-high mark. You may not feel the altitude strongly, but hot water still dehydrates you faster at elevation. UV is about 28% stronger than at sea level, so bring sunscreen and drink more water than you normally would.

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Temperature
109°F
Warm Hot Boiling
Water Temp 109°F (43°C)
Avg Air Temp 38°F
Above Ambient +72°F
Great soaking conditions September
Access
Road Access Roadside
Nearest Road Valley Road
Distance to Road 252 ft
Frequently Asked Questions
What is the water temperature at Pierson Hot Springs?
Pierson Hot Springs has a water temperature of 109°F (43°C). This is considered a hot spring, well above body temperature.
Where is Pierson Hot Springs located?
Pierson Hot Springs is located in Blaine County, Idaho at 6,900 feet elevation, near Ketchum. Coordinates: 43.9900°N, 114.8000°W.
How do I get to Pierson Hot Springs?
Pierson Hot Springs has Roadside road access, with the nearest road being Valley Road (252 ft from the road).
Can I camp near Pierson Hot Springs?
Yes, Alturas Lake Picnic Area (Id) is located nearby (5.1 miles away).
What minerals are in the water at Pierson Hot Springs?
Water chemistry analysis shows the presence of pH, Calcium, Magnesium, Sodium, Sulfate, Chloride. The pH is 9.3 (alkaline).
Sources: USGS NWIS