Absolutely! That is one of the best aspects of the Finnish climate. Helsinki experiences four very distinct seasons, so it is never boring. You can do anything from winter sports to summer sports. The winters are cold and snowy (temperatures typically below 0 Centigrade); the spring is full of flowers; the summers are often very warm and extremely light (due to the northern latitude, the sun hardly sets at all in the summer) and the autumn tends to be cold and rainy (the worst season perhaps - though this is when the forests are full of berries! Great for picking). Enjoy!