Yellowstone Hot Springs Temperature

Yellowstone National Park is home to one of the most extraordinary geothermal systems on Earth, with over 10,000 hydrothermal features, including hot springs, geysers, mudpots, and fumaroles. These hot springs vary in color, size, and temperature, depending on their depth, mineral content, and connection to underground heat sources. 

The temperature of Yellowstone’s hot springs is not uniform; it can range from comfortably warm pools to dangerously boiling waters. Understanding these temperatures not only reveals the geological marvel beneath the park but also explains why swimming is prohibited in most thermal features.

Quick Reference: Yellowstone Hot Springs Temperature

Hot Spring	Location	Approx. Temperature (°F / °C)	Description
Grand Prismatic Spring	Midway Geyser Basin	160–189°F / 71–87°C	Largest hot spring in the U.S., known for its rainbow-colored rings caused by thermophiles.
Excelsior Geyser Crater	Midway Geyser Basin	Up to 199°F / 93°C	Massive hot spring releasing over 4,000 gallons of boiling water per minute into the Firehole River.
Mammoth Hot Springs	Mammoth Area (North)	149–165°F / 65–74°C	Terraced formations of travertine; cooler but still dangerously hot.
Emerald Spring	Norris Geyser Basin	~154°F / 68°C	Deep, emerald-colored pool with fluctuating heat levels.
Porcelain Basin Pools	Norris Geyser Basin	Up to 199°F / 93°C	Among Yellowstone’s hottest regions with near-boiling water.
Morning Glory Pool	Upper Geyser Basin	~165°F / 74°C	Brilliant blue-green pool affected by human activity, slightly cooler than in the past.
Chromatic Pool	Upper Geyser Basin	158–170°F / 70–77°C	Displays gradient color changes due to varying temperature zones.
Beauty Pool	Upper Geyser Basin	158–170°F / 70–77°C	Deep blue pool adjacent to Chromatic Pool; both share underground connections.
Fountain Paint Pot Area	Lower Geyser Basin	160–190°F / 71–88°C	Features hot springs and bubbling mudpots, depending on moisture level.
West Thumb Geyser Basin Pools	Near Yellowstone Lake	180–200°F / 82–93°C	Hot springs located near and even under Yellowstone Lake’s shoreline.
Underwater Hot Springs (Yellowstone Lake)	Beneath Yellowstone Lake	180–200°F / 82–93°C	Submerged geothermal vents showing activity beneath the lake bed.

One of the most famous and visually stunning features in the park is the Grand Prismatic Spring in the Midway Geyser Basin. Known for its rainbow-colored rings, Grand Prismatic is also one of the largest hot springs in the world. Its center reaches temperatures of around 160°F to 189°F (71°C to 87°C), which is hot enough to prevent most life forms from surviving. The vivid colors around its edges are created by heat-loving microorganisms called thermophiles that thrive in slightly cooler water, forming orange, yellow, and green bands as the water temperature decreases toward the perimeter.

Nearby lies the Excelsior Geyser Crater, another fascinating thermal feature. Once a powerful geyser, Excelsior is now a massive hot spring with a surface temperature of about 199°F (93°C). It discharges more than 4,000 gallons of boiling water per minute into the Firehole River. The water in this spring is scalding hot, and the constant flow of steam makes it appear like a boiling cauldron. Despite its intense temperature, Excelsior is a striking example of geothermal power, showing how active Yellowstone’s underground system remains.

The Mammoth Hot Springs, located near the park’s northern entrance, have a completely different character. The terraces here form from calcium carbonate deposits that create flowing, white travertine formations. The temperatures of Mammoth Hot Springs generally range between 149°F and 165°F (65°C to 74°C). Although cooler than some other features in the park, these hot springs are still too hot for direct contact. The temperature varies significantly depending on the location of each terrace and the rate at which the hot water flows through underground channels.

At the Norris Geyser Basin, one of the hottest and most dynamic areas in Yellowstone, the hot springs can reach temperatures close to the boiling point. In this basin, some springs are measured at over 200°F (93°C), with certain deeper sources exceeding that temperature due to high underground pressure. The Emerald Spring, for instance, maintains an average temperature of around 154°F (68°C), while the nearby Porcelain Basin is known for pools that hover around 199°F (93°C). This area constantly changes due to seismic activity, causing fluctuations in temperature and water flow.

Moving to the Upper Geyser Basin, where Old Faithful erupts, visitors will also find many hot springs with impressive heat levels. The Morning Glory Pool, famous for its bright blue and green hues, has a temperature of around 165°F (74°C). Over time, debris thrown by visitors has partially clogged its vent, slightly cooling the pool and altering its color. Close by, the Chromatic Pool and Beauty Pool have temperatures ranging between 158°F and 170°F (70°C to 77°C). These pools display stunning gradients of color as the temperature transitions from scalding hot at the center to cooler edges.

In the Lower Geyser Basin, the Fountain Paint Pot area features a mix of hot springs and mudpots. The temperatures here vary from 160°F to 190°F (71°C to 88°C), depending on the water level and gas activity. The bubbling mudpots form when hot water mixes with volcanic clay, and their temperature depends on the amount of water present—less water means thicker, hotter mud.

Even in smaller or lesser-known areas, the heat remains extreme. Springs in the West Thumb Geyser Basin, located near Yellowstone Lake, often register between 180°F and 200°F (82°C to 93°C). The presence of geysers underwater near the lake shore is a reminder that the geothermal system extends beneath the massive lake itself. In fact, scientists have discovered underwater hot springs in Yellowstone Lake that maintain similar temperatures to those seen on land, making it one of the most geothermally active lake beds in the world.

Overall, the temperatures of Yellowstone’s hot springs illustrate just how powerful and active the geothermal system beneath the park truly is. While each spring’s heat varies depending on depth, pressure, and chemical composition, most are far too hot for any safe human contact. Instead, their beauty lies in observation—from the brilliant blues of Grand Prismatic to the chalky whites of Mammoth. These hot springs are not just natural wonders; they are windows into the Earth’s fiery core, reminding every visitor that Yellowstone sits atop one of the most active volcanic systems on the planet.