Old Faithful Geyser: What to Know
Why 90 minutes?
Old Faithful is predictable because of its plumbing: a hot-spring chamber fills, heat builds pressure, water flashes to steam, and eruption happens. The cycle is roughly 90 minutes, but it varies — sometimes 65 minutes, sometimes 110. The NPS Yellowstone app estimates the next eruption time based on recent patterns. The app takes the guesswork out of timing. On a guided tour, your guide checks the app and positions the group to watch. On a self-drive, download the app and plan your timing.
What an eruption looks like
An eruption is short — a few minutes of the famous column, then the crowd thins fast. It is loud, dramatic, and over quickly. Most visitors watch for 2–3 minutes and then move on (or take photos). The geyser is surrounded by a boardwalk and benches, so you can sit and wait for the next eruption if you miss the current one. Morning and dusk light is best for photography.
The Upper Geyser Basin: more than just Old Faithful
Old Faithful sits in the Upper Geyser Basin, which has dozens of hot springs, geysers, and boiling pools. A full walk around the basin is 2–3 hours and takes you past Morning Glory Pool (a brilliantly colored hot spring), Castle Geyser, and Fountain Paint Pot. Most one-day tours spend 1–2 hours in the basin (watching Old Faithful + a quick walk). If you want a deeper dive, stay longer or book a multi-day package with more time.
Old Faithful erupts ~90 min apart. Check the NPS app for the next predicted eruption. The basin walk is 2–3 hours if you do it all; most tours spend 1–2 hours.
Frequently asked questions
How often does Old Faithful erupt?
Roughly every 90 minutes, though the interval shifts eruption to eruption. The NPS Yellowstone app publishes the next predicted window — check it and build your basin walk around it.
Does it cost money to see Old Faithful?
No. It is included in the $35 park entrance fee. On a guided tour, the tour operator pays the fee (some tours include it in the price, some charge separately). See the fee guide for details.
How long should I spend at Old Faithful?
Most people watch the eruption (2–3 min) and take photos, then move on. The surrounding Upper Geyser Basin walk is 2–3 hours full loop with Morning Glory Pool, Castle Geyser, and Fountain Paint Pot. On a day tour, you get 1–2 hours; on longer packages, more time.
Can you predict when it will erupt?
Yes. The NPS app predicts eruptions based on recent patterns. Guides check it before positioning the group. If you miss one eruption, you can wait for the next (roughly 90 min later).