Winter in Norway is from December to March. The mercury dips a few degrees below freezing point. Snowfall in winter is a common phenomenon. However, winter also makes Oslo a great winter sports venue.
Oslo presents a range of tourist opportunities all throughout the year. However, if you are looking for the outdoors, March to October is the best season to get comfortable. Summer in Oslo is June to August. It is surprisingly warm in the summer with an average temperature of 26 degrees centigrade, because of the Gulf Stream waters.