@xixiangdong They are visible in Finland between September and March, according to the Visit Finland website. I see them extremely seldom, but I suppose I should be more alert when they are about to appear. They are much more frequent in Lapland (northern Finland, Sweden and Norway).
So it ALMOST makes you like winter. π I understand you. We are so "spoiled" with very long, dark and cold winters, that I like summers more. A tropical beach is the most exotic thing I can experience. To visit a beach/an island in Spain, Greece, Thailand, Goa... is paradise for me (even if the countries are not paradises on earth).