The cause of that change in the weather is not what you think.

  In the case of classically chaotic systems, (the weather) the non classical quantum world has a dramatic effect. 

This means that systems like the weather turn out to be ‘branching’ all the time due to     QUANTUM decoherence interactions, so that what we usually think of as classical unpredictability, could be rain tomorrow... is in fact quantum indeterminism!