The first sign of spring for me is forgetting my gloves and then not thinking, "Brr - oh crap, I forgot my gloves."
The second sign of spring for me is feeling a breeze and thinking "Ah, nice breeze" and not "oh crap, I forgot my gloves."
The third sign of spring for me is being able to have the window cracked, with all the multifarious noises that entails.