Exploring Helsinki during December means diving into a world of festive markets, savory glögi, and joulutorttu pastries. The frosty air adds an extra layer of magic to the journey on the Santa Claus Express towards Rovaniemi. If you're planning a visit in May, enjoy Lapland's warmer weather with temperatures reaching a delightful 28°C; it’s perfect for outdoor adventures without bundling up too much.