You cannot predict the future.

Chaos theory throws it right out the window. It says that you can never predict certain phenomena at all. You can never predict the weather more than a few days away. All the money that has been spent on long-range forecasting — about half a billion dollars in the last few decades — is money wasted. It’s a fool’s errand. It’s as pointless as trying to turn lead into gold. We look back at the alchemists and laugh at what they were trying to do, but future generations will laugh at us the same way. We’ve tried the impossible — and spent a lot of money doing it. Because in fact there are great categories of phenomena that are inherently unpredictable.

Forecasts may tell you a great deal about the forecaster; they tell you nothing about the future.

who wants to be foretold the weather? It is bad enough when it comes, without our having the misery of knowing about it beforehand.

Prediction is very difficult, especially about the future.

When the number of factors coming into play in a phenomenological complex is too large scientific method in most cases fails. One need only think of the weather, in which case the prediction even for a few days ahead is impossible.

The inability to predict outliers implies the inability to predict the course of history

the only thing that can be predicted is the probability of different events.

...[I]t is simply impossible to predict the effects of lifetime exposure to chemical and physical agents that are not part of the biological experience of man.

To predict tomorrow's weather, I need not take into account the state of mind of the Emperor of Manchukuo.

It is impossible to foretell the future with any degree of accuracy, that it is impossible to rehearse life. A fault in the scenery, a face in the audience, an interruption of the audience on to the stage, and all our carefully planned gesture mean nothing, or mean too much.

All predictions are wrong, that's one of the few certainties granted to mankind.

You can only predict things after they have happened.

It's tough to make predictions, especially about the future.