Balmy Breezes

Why is it that in July, when it's 62 degrees in the evening with a light breeze, I can sit in front of the open sliding door and knit happily away, enjoying the night sky, but in February when it's 62 degrees in the evening with a light breeze, I am so bulked up in sweaters - and that's with the heat going - I can hardly move my arms and fingers?