OLD FAITHFUL GEYSER is on most people’s top thermal feature to see when visiting Yellowstone. You can wait on the benches or in the shade of the trees, or you can take a walk on Geyser Hill as Old Faithful is visible from most of it.
WATCH FOR: Pre-play splashes signal the eruption will probably happen in the next ten minutes or so. Down below are larger bubbles starting to rise, and as they rise, they push the water above them out. Yet it’s still not quite hot enough yet for the eruption where a large area of water turns to steam. They do get you ready with your camera, but there can be many of these. Eventually, one of these is actually the start the eruption. Then the famous geyser takes 20-30 seconds to reach full height before descending to a lower height to finish out the eruption. If you want a photo of you with the geyser at full height behind you, don’t wait too long. But if you miss it, usually you’ll have another opportunity as Old Faithful erupts 9 or 10 times during daylight hours in the summer. While many people believe Old Faithful is truly predictable, it is like all geysers and the only forecast window they can predict is the next one. Predicting further out requires more consistency than any geyser is willing to give.
May 2017: The current average interval is 96 minutes. This is used along with eruption duration to calculate the next prediction.