Climate Chart of Helsinki, Finland

Climate overview

Temperature

The coolest monthly mean is -2.7 °C in January, while the warmest is 17.1 °C in July. These are averages for each month, not typical daytime maximum temperatures, so they do not describe the full range visitors may encounter within a day. The unweighted mean of the monthly means is 6.6 °C; it summarizes the calendar-month averages rather than representing a day-weighted annual average.

Sunshine

Average daily sunshine is highest at 13.77 hours/day in June and lowest at 0.98 hours/day in December. These duration averages can help set expectations for daylight outdoor planning, but sunshine hours are not the same as day length and do not guarantee clear conditions on a particular day. The unweighted mean across the monthly averages is 7.11 hours/day per day.

Rain

Mean daily rainfall reaches its monthly high of 2.82 mm/day in August and its low of 0.60 mm/day in March. These are daily averages within each month, not monthly rainfall totals, and the lower mean does not guarantee rain-free days or indicate how often rain falls. Across the monthly means, the unweighted average is 1.58 mm/day.

Snow

Mean daily snowfall has its highest monthly average in January, at 10.24 mm/day; the unweighted mean of the monthly snowfall averages is 3.14 mm/day. These amounts describe daily means, not monthly totals. They do not establish how many days have snowfall, how deep snow becomes, whether it remains on the ground, or whether conditions suit skiing.