Old Faithful has been a top attraction of Yellowstone since the park was established nearly 150 years ago. After each Old Faithful eruption, rangers predict when the next one will be. From over 100 years of recording data, we know if an eruption is longer than 3 minutes, it will be 95 (+/- 10) minutes until the next eruption. If it's under 3 minutes, then it will be 66 (+/- 10) minutes until the next eruption.
Last updated: September 24, 2020