Went to Helsinki and wow the people were very friendly the shopping was very good indeed they have some wonderful shops there and there is a great shopping mall at Itkeskus this is all indoors and the rail system stops directly beneath the centre so even on those cold days you will be fine.

Sightseeing a ferry trip to Suomenlinna is worth a visit in the winter the ferry crunches its way through the sea ice. Good rail system for traveling around and the over night ferry to Stockholm is cheap and i would book at the ferry rather than online.