In general, when booking your flight to Helsinki, March is the cheapest month on average.
On average, from most locations, when planning your trip to Helsinki, try to book your flight in the region of 53 days in advance for the cheapest prices.
On average, the cheapest flights to Helsinki are found when departing on a Wednesday. Try to avoid departing on a Sunday, as this is usually the most expensive day.
On average you can find the best deals on plane tickets to Helsinki when looking for flights with morning departure times.