Predictions are shown in Mountain Time.
Eruptions cannot be predicted with absolute certainty and estimates are derived from user reports.
Eruptions cannot be predicted with absolute certainty and estimates are derived from user reports.
| Geyser | Prediction |
|---|---|
| Castle |  22:59 ± 1 hour |
| Grand | 20:04 ± 1 hour |
| Old Faithful | 17:17 ± 13 minutes |
Predictions courtesy of:
GeyserTimes
National Park Service (*) Prediction derived from double interval