Category Archives: Prediction

Prediction Service Down

Just a heads up. The main prediction server ( for GeyserTimes is currently down. The server crashed and Alan has to rebuild the server that provided the predictions. In the meantime we have been working on a new prediction engine that will be hosted on our own server to eventually replace the current server. The new system is not fully ready yet but we have released part of it so we will at least have predictions for Old Faithful. We hope to get the prediction server and/ or the GeyserTimes prediction engine fully operational in the near future.


Geyser Predictions

Geyser predictions are wonderful aids in planning a geyser-gazing itinerary.  However, they are not to be trusted blindly.

The National Park Service predicts 6 geysers: Old Faithful, Grand, Castle, Daisy, Riverside, and Great Fountain.  These geysers have large eruptions and are mostly stable in their eruptive behavior which allows them to be predicted.  Even then, the NPS uses language like “may erupt between X and Y.”  May erupt, might, possibly, could.  All the qualifying phrases are necessary when talking about geyser predictions.

We offer predictions of other geysers on GeyserTimes.  Geysers like Beehive and Fountain are spectacular and can enter into phases of “predictability.”  However, there are good reasons that the NPS does not predict them.  Fountain Geyser is in the Lower Geyser Basin and it is more difficult to keep track of its behavior.  It’s also a constant risk that a visitor will receive a prediction of “noon to 2pm,” arrive at Fountain just after noon, wait, wait some more, then eventually leave (frustrated and angry) not knowing that Fountain erupted at 11:50am.

For a geyser like Beehive, a prediction with the same accuracy of other NPS predictions (about 90%) might require a really wide time window of perhaps 6, 8, or 10 hours.  It doesn’t feel like much of a helpful prediction at that point, especially considering the average visitor’s time in Yellowstone is about 2 days total.

Despite these challenges, or perhaps because of them, predicting is fun.  We are making our own geyser predictions that you can use–just know the risks that could lead to you sitting somewhere for many hours waiting and hoping!

Ultimately it is up to you to determine if a geyser has a chance to erupt or if it has already erupted recently and it’s best to move on.  There are several resources that can help you including  You can also attempt your own predictions by looking at recent activity of a geyser on GeyserTimes.  Good luck and happy gazing!