I'm still confused about global warming

I'm still confused about global warming.  Apparantly these extremely hot days are proof of this, but isn't this summer?  For all my 60+ years there have been hot days and bushfires in summer.  My parents and my grandparents told us stories of how they coped with hot weather before airconditioning and refridgeration.    So, if this is global warming, can anyone explain to me why there are icicles on citrus trees in "sunny" California and why some parts of North America had records amounts of snow at xmas time?