All predictions are shown in Mountain Time.
Predictions are NOT 100% accurate. For more on predictions: Read This
GeyserPrediction
CastleGeyserTimes 03:56 ± 45 minutes
GrandGeyserTimes 07:33 ± 1 hour

Predictions courtesy of:

GeyserTimes GeyserTimes
NPS National Park Service

(*) Prediction derived from double interval