My cat, Oli, has also noticed that snow no longer terrorizes his neighborhood.  More so, he’s hearing the birdies chirp and watching the squirrels scamper around.  So, now he sits by the door and cries to go outside.  I’m a bit nervous about this, as he chews on grass, recently threw up a worm, and once got a big gash in his back when outside.  But one day, he wouldn’t let up with the yowling.  So I caved.
Outside Oli went, with me in tow.  He rolled around on the stone floor of the little porch.  He sniffed around at God only knows what.  When I decided it was time to go inside, Oli was quite reluctant.  He crouched down and didn’t look at me.  I scooted him towards the door and opened it, where he rolled around on the dirty stones again, then looked up at me with his “But Mommy, just three more minutes!” eyes.  My neighbor chuckled and commented that Oli likes the warm weather also.  When I glanced up at him, the brat cat dashed sideways towards the woods.  And within two leaps, he was six feet up a tree.  I screamed and ran after him, stopped at the bottom of the tree, and demanded for him to get down.  Fortunately, he obeyed.  I scooped him up and hugged Oli to me to carry him inside. 
But this was a good sign.  He’s got his energy back.