The weather is predictable to around 14 days, said Meteorologist Dave Unger, of the Climate Prediction Center. What can make predicting weather challenging however, he continued, is that weather projections can be off by one day from about eight days out.

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This makes planning a specific event difficult, Unger said, because you can only get a general sense of weather from day-to-day, from around seven days out.

“Imagine, for example, that an event is moved from Saturday to Sunday on the basis of a forecast of rain eight days ahead,” he said. “We meteorologists know that the weather system that is predicted to cause the rain can easily come one day early or one day later than predicted, since the event is more than a week away. If the rain event comes later, Saturday could have been a nice day, and Sunday could have been rainy.”