Another difference people forget about when you think of recoil is, winter means winter jackets which due to insulation are padded. Summer means T-shirts which give you no protection from recoil.

I was shooting today and it was 84ºs. It was the first time in a long time that the scope skimmed/touched me. But a lot of the time that is more due to sloppy holding the rifle then recoil catching me.