Weather vs Climate
Weather is the short-time-scale (< a few days)
evolution of the of the atmosphere.
Climate is the statistics of weather.
Weather prediction.  The evolution of the state variables
of the atmosphere is governed by nonlinear dynamics (i.e.
“chaos”), and is therefore inherently unpredictable beyond a
certain period of time.
Climate prediction.  There is no reason to doubt the
predictability of the statistics of weather.