Summer of course. +30*C is better than -30*C for me. Plants growing, birds singing and warm wind whiffing. Is possible to wear t-shirts, shorts, sneakers and cap at night. Forrest has green color and extreme cycling is possible. However I see positives of winter. Christmas, New Year, skiing, snowball battles... I like that spring come after winter because fauna and flora wake up to life and world is full of colors. Flowers smells fantastic, sun is bigger and day is longer so my vote is for summer