Gee, how fast the time runs! I haven’t noticed when the summer happenned and it is officially autumn already, duh! Yep, it’s autumnal equinox today!
Congratulations with The First Day Of The Fall! 
From official sources: At the autumnal equinox (Sept 22, 2008; 11:44:18 A.M. EDT), the Sun appears to cross the celestial equator, from north to south;
this marks the beginning of autumn in the Northern Hemisphere.
And for those of us, with poetic inclination:
When autumn wind goes running
It does some magic things.
It gives the shadows dancing shoes
It gives the bright leaves wings
When autumn wind goes running
It curls the bonfire's tail of smoke
And shares a little whispered joke
With cornstalks who delight to prattle
It turns a seed pod into a rattle
When autumn wind goes running