You can visit Finland anytime, but the months of May through September offer the mildest weather and the greatest number of tourist attractions. Late spring, especially May and June, are the most pleasant months in Finland. Finns take their summer vacations in July, which means higher prices, some business closures, and the need for advance reservations. After that, August and September have more annual rainfall than the prime spring and summer months.
Enjoy the Warm Weather
During May or June, the weather in Finland will be warm and outdoor activities and events are plentiful. Just a few of the many spring and summer events in Finland include Black and White Theatre Festival in June (2018's is the 100th celebration), Organ Night and Aria Festival from June through August, Naantali Music Festival in June, Midnight Sun Film Festival in Jun, Juhannusvalkeat (Midsummer) Festival,(with bonfires, folk music and dancing), Sirkus Finlandia, and Pori Jazz Festival in July.
In Helsinki during August? The city's annual Flow Festival is worth its €99 (one day) price tag. The festival is held in an abandoned power station on Helsinki's outskirts and is host to some of the planet's most desired acts. Not to mention an impressive food menu, (with extensive vegan, organic and farm-to-table selections) and beautiful design—don't miss a show at the Bright Balloon 360 stage, an immersive round venue with a stage in the center.
In 2018 the festival will take place on August 10-12 and feature headliners including Kendrick Lamar, the Arctic Monkeys, and Patti Smith. But look out for Finnish acts too—Alma is one of the country's favorite singer-songwriters. Flow Festival is definitely one of the coolest—and most unique—festivals in Europe.
In Finland's north, the midnight sun is best seen in June and July.
Winter Also Works
At the other end of the spectrum are winter travelers. If you count yourself among this group, then the colder season may be the best time for your visit. Which winter months are best to visit Finland will depend on the kind of activities you like. If you want to see the Northern Lights (Aurora Borealis), aim for December. It's a pricey time of year, but Christmas in Finland, packed with snow and local events, is a great experience. Don't forget to visit Santa in Lapland.
If you are a winter sports enthusiast, when to go to Finland is flexible. January through March are the coldest months in this Scandinavian country. At least you'll have more hours of daylight than you do in December because the polar nights will have ended by this time. This can be a good thing because the polar nights, while a great time to view the Aurora Borealis, also encompasses a two-to-three-month period when the sun literally never shines over Finland.
Alternative Times to Visit
September and October are good times to visit Finland if you're on a budget and want to avoid the high tourist season. However, with the diminished crowds, many attractions will be closed.
Still, photographers may relish "the New England-style burst of autumnal color in September and October," Responsible Traveler notes.
So, if you don't mind missing out on the festivals and concerts, but enjoy the thought of quiet and pleasant walks, beautiful landscapes, and relatively mild weather, then early fall may be the best time for you to visit Finland.