Because of Helsinki’s harsh winter conditions, the best time to visit the city is between June and September. You’ll enjoy longer sunlight hours, happier locals, and a mild climate. If you consider yourself an outgoing type of person, then the month of August presents the ideal atmosphere for meeting new people because most of the city’s festivals are held during this month. Arriving in Helsinki during the shoulder seasons is pretty dicey because the weather can be rather unpredictable. And, unless you are a winter extreme sports enthusiast or dislike the sun in general, the coldest months are to be avoided.