Helsinki, the capital of Finland, sits on the country's southern Baltic coast on the Gulf of Finland at approximately 60.17°N, 24.94°E — far enough north that it sits near the 60th parallel, yet milder than its latitude suggests thanks to the moderating Baltic Sea and the warmth carried by the North Atlantic Current. It has a Baltic, moderately continental climate (Köppen Dfb) with cold, dark, snowy winters and mild, bright summers, and dramatic swings in daylight between the seasons.

Summer, from June to August, is mild and pleasant rather than hot, with July the warmest month — average highs around 21–23°C and cool nights. Genuine heat above 30°C is rare on the coast; the record high for the city is only about 31.6°C. The magic of the season is the light: around midsummer the 'white nights' mean it never gets fully dark, with up to 18–19 hours of daylight, and the long luminous evenings draw the city outdoors. It is also the wettest time, with July and August seeing the heaviest rain and occasional thunderstorms.

Winter, from December to March, is long, cold, dark and snowy, with January and February the coldest months — average highs around -1 to -3°C and lows near -6 to -9°C. Arctic cold snaps can plunge temperatures below -20°C, and the record low is around -34°C, though the sea keeps the coast milder than inland Finland. Snow blankets the city for months, the sea can freeze, and midwinter days are strikingly short, with only about six hours of daylight in December and the sun setting by mid-afternoon.

Helsinki receives moderate precipitation, around 650–740 mm a year, with the wettest period in late summer and autumn (July, August and October) and the driest in spring around March and April. A large share of the cold-season total falls as snow, which can lie deep from around Christmas through March, and permanent winter snow cover is the norm. Live rainfall, humidity, and pressure readings for the city are shown in the panels above.

The defining feature of Helsinki's climate is the extreme seasonal swing in daylight rather than sheer cold: from the barely-dark 'white nights' of midsummer to the six-hour days of midwinter, the light governs the rhythm of the city. The Baltic can freeze in hard winters, autumn and early winter bring the strongest coastal storms, and clear winter nights occasionally reward the city with a glimpse of the Northern Lights.

To follow any single measurement in Helsinki more closely, use our live instruments: the online barometer for atmospheric pressure, the thermometer for temperature, the hygrometer for humidity, the anemometer for wind speed, the wind vane for wind direction, and the rain gauge for rainfall.