All else being equal, every 25 deg F is usually about 1 jet size (e.g. 180 to 182). Sometimes 1 size for every 20 deg works out better because the humidity in the air tends to go up and down with temperature.
Winter = cold and dry = lots of oxygen in each unit of air.
Summer = hot and humid = less oxygen in each unit of air.
There's a "How To" on finding the best pilot jet and fuel screw setting. If you don't want to go through that procedure then backing out your fuel screw 1/2 to 1 turn is probably a safe bet.
If you know for sure that your jetting was correct for summer temps then it's fairly accurate to rejet based soley on temp/humidity/elevation changes. If your only pretty sure your jetting was spot-on then go ahead and make changes for conditions--but don't assume what you've done is correct. Be sure to test the results of your changes. What I'm getting at is that if you maybe where a little fat in the summer then you might be pretty close to correct right now.
"It ain't what you don't know that gets you into trouble.
It's what you know for sure that just ain't so. "
--Mark Twain