Predictions are shown in Mountain Time.
Eruptions cannot be predicted with absolute certainty and estimates are derived from user reports.
GeyserPrediction
CastleGeyserTimes 18:19 ± 1 hour
CastleNPS 18:30 ± 45 minutes
Great FountainNPS 15:15 ± 2 hours
Old FaithfulGeyserTimes 16:28 ± 13 minutes
GrandNPS 22:00 ± 45 minutes
GrandGeyserTimes 22:20 ± 1 hour
RiversideGeyserTimes 22:05 ± 25 minutes
Old FaithfulNPS 17:59 ± 10 minutes
RiversideNPS 22:00 ± 30 minutes

Predictions courtesy of:

GeyserTimes GeyserTimes
NPS National Park Service

(*) Prediction derived from double interval