Weather forecasts are notoriously iffy, and accuracy drops with time, but we understand the physics behind it (to a large extent). There's also a lot of fine-grained data available. For some arbitrary time series, there's only one data sequence, and the model is unknown. Extrapolation then becomes a lot more magical.

Whether forecasting is simple: it either rains or it doesn’t. 50/50 probability!

And JPG doesn't work either..