I did wake up feeling a bit cold, and had my window closed over night for the first time in a few months.
Going to the car at 6:15 this morning was also pretty cold, but still not bad enough for me to start wearing a jumper of jacket.
It's still summer, so I therefore refuse to wear jumpers of jackets, no matter how cold it gets. (only exception is if it's raining really hard, and I have to be out in it)