temperature in helsinki in august
Helsinki: Annual Weather Averages. July is the hottest month in Helsinki with an average temperature of 17Â°C (62Â°F) and the coldest is February at -6Â°C (22Â°F). The wettest month is August with an average of 90mm of rain. The best month to swim in the sea is in August when the average sea temperature is 13Â°C (55Â°F). Loading weather data.