turbo cars in general LOOOOOOVE the cold. the colder the better. cold air also tend to be dry, which is also better. the atmospheric cold air cools the intercooler better which in turn significantly cools the (turbo) pressurized intake air, delivering more power, as the computer can adjust timing, AFR, boost, etc. to play happy with the cold air. back in my subaru days, car had more power you could feel when it was cold out. the colder and dryer the air the happier a turbo engine is (cold allows a denser fuel mix too). the opposite is the inverse, the hotter and more humid the air, the less happy the turbo engine is as cpu has to retard timing, enrich the fuel mixture, etc creating a bit less power.
you are just feeling your car have a bit more power... .
2013 X3 28i, AW, Chestnut, Sienna, ZAP, ZCV, ZCW, ZDH, ZPP, DHP, rear view, park distance, cargo net (Wife's)
2010 Porsche Boxster S (Mine)