Best time to travel to Yellowstone National Park

Grand Prismatic Spring in Yellowstone National Park 2025

As the name implies, this is the largest and possibly the most spectacular hot spring in the USA

Best time: June–August

The Grand Prismatic Spring is located in the Midway Geyser Basin and aside from being the largest in the United States, it's also the third largest in the world. It is around 110 m in diameter and 50 m deep.

Because of its temperature (around 70 °C), the boiling water from underground is sterile, which makes the centre of the lake so clear and blue. The spring is framed by red, orange, yellow and green rings which are getting deeper or fade depending on the season. This unusual effect comes from the mats of colourful pigmented bacteria and microbes that live in the warm mineral-rich waters around the spring.

Although the Grand Prismatic Spring looks absolutely stunning, you shouldn't be tempted by its beauty and try to walk off the designated boardwalk. This boardwalk is made not only to protect visitors from the boiling liquid but also to keep the natural environment of the spring from damage. So while visiting this natural wonder make sure you're being careful and respectful to nature.

The best time of the year to visit the Grand Prismatic Spring is summer. The colours are at their brightest when the mats turn red and orange, and blue water contrasts with them. Moreover, summer months are generally better for getting around the park, and in terms of weather. Visitors also share some tips regarding the timing of the day, suggesting to be in the area at around noon for brighter colours and thus better pictures.

Practical info

What makes Grand Prismatic Spring such a unique natural wonder?

Grand Prismatic Spring is the third largest hot spring in the world, which is rich in minerals that support a vast array of bacterial and microbial colonies creating multi-hued rings of vibrant colors. It spans around 110m in diameter and 50m in depth and is situated in beautiful surroundings at Yellowstone National Park that makes it one of the unique natural wonders in the United States.

What is the best time of the year to visit Grand Prismatic Spring?

The summer months from June to August are the ideal time to visit Grand Prismatic Spring as this is the time when the bright pigmented mats of bacteria take on vibrant colors of red and orange that contrast amazingly well with the deep blue water of the spring. The visitors should come around noon to capture the brightest colors and get better pictures while being able to take advantage of the regularly favorable weather of the site.

Can we take a dip in Grand Prismatic Spring?

No, visitors are not allowed to take a dip in Grand Prismatic Spring due to its high temperature, reaching around 70°C. The water from the spring is also sterile and keeping it that way is essential to maintain its clarity and deep blue color. Boardwalks are provided for visitors instead so that they can admire the beautiful colors of the hot spring while also preventing damage to the environment around the spring.

What is the meaning behind the distinctively vibrant colors surrounding the spring?

The distinctively vibrant colors encircling Grand Prismatic Spring come from a specific kind of thermoacidophilic bacteria and microbes that can thrive in very high-temperature environments. These bacteria are so abundantly present and develop distinctive colors of mats throughout various seasons, with red and orange being more vibrant during summers and green and yellow colors more dominant in winters. The colors created by the microbial mats are one of the main reasons people visit the natural wonder of Grand Prismatic Spring.

Are there any restrictions on visiting Grand Prismatic Spring?

Visitors need to adhere to certain restrictions when visiting Grand Prismatic Spring at Yellowstone National Park. They can explore the area designated for boardwalks only, stay on the assigned path and avoid venturing off into the unstable terrain. Any other access can cause significant damage to the environment, which may not support human activity well. Additionally, the visitors should also avoid littering and throwing any item into the spring for the same reason.