What September feels like in Helsinki
September is early autumn in Helsinki. Daytime feels cool and fresh rather than cold. There is little difference between day and night: nights are cool, and evenings feel much like the afternoon. The air is damp, which makes cool temperatures feel colder, particularly in wind.
Rain in Helsinki in September
Expect a mix of dry and wet days, with rain about one day in 3. Each rainy day adds about 5.7 mm (0.2 in), a proper wetting rather than a sprinkle. The yearly figure is similar, around 5.2 mm per wet day.
Daylight and sunshine in September
On 15 September the sun rises at about 6:45 am and sets around 7:46 pm local time, giving 13 h of daylight. Evenings are drawing in — 2 h 46 min less daylight than mid-August. Measured sunshine covers about 64% of the daylight — there are plenty of bright spells.
How September compares to the rest of the year
Ranked by average high, September comes out as the 4th warmest month in Helsinki. Against August, the average high is 4.7°C (8.5°F) lower, with 15 mm less rain. The cooling trend carries on into October. October averages a high of 8.9°C (48°F).
Who September suits
- Sightseeing: a good fit — comfortable enough to explore on foot all day.
- Parks & outdoor: a good fit — pleasant for gardens, parks and riversides.
- Beach: less ideal — the sea air is too cool.
Tips for visiting Helsinki in September
Rain Protection
Keep a small umbrella in your bag and wear shoes that cope with puddles.
Light Jacket
A light jacket or knit layer is enough for most of the day.
Sunglasses
Plenty of sun, so bring sunglasses and a cap.
Quick questions
How warm is Helsinki in September?
Expect around 15.2°C (59.4°F) in the afternoon and 10.4°C (50.7°F) at night, which most visitors would call cool.
Does it rain a lot in Helsinki in September?
Yes, fairly — rain falls about one day in 3 and totals about 68 mm, so an umbrella is worth carrying.
What should I wear in Helsinki in September?
The numbers point to rain protection, a light jacket and sunglasses. There is little need to change for the evening.
Is September or October better for visiting Helsinki?
On our 12-month climate ranking, September comes out ahead (#5 of 12 vs #7). October is cooler.