Helsinki in September usually sees fair weather conditions, with an average daily high temperature of +57°F and roughly 5 sunny days. However, you should prepare for about 16 rainy days with an average precipitation of 78 mm. The weather is changeable so pack for every eventuality. Search flightsin one click on Avionero.
Average weather
☀️
+57°F
Avg. max. temperature
+32°F
Min.
+72°F
Max.
78 mm
Total precipitation
81%
Avg. humidity
4 m/s
Avg. wind
5 ☀️
Sunny Days
8 ⛅️
Cloudy
16 🌦
Rainy
Our opinion: Helsinki has OK weather in September.
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Average temperature in Helsinki in September
Here are the expected maximum, average and minimum temperatures in Helsinki for September based on the historical data.
Last Year
Historical Data
The temperature in September is +64°F on average, with a range between a maximum of +70°F during the day and a minimum of +43°F at night.
The average maximum temperature goes down 20% by the end of the month, compared with the beginning of the month, from +66°F to +61°F.
Is Helsinki warm or cold in September?
Helsinki is typically mild in September.
Maximum temperatures go down compared to the previous month from +66°F to +57°F. The minimum temperature also goes down from +55°F to +48°F.
Pack a light jacket as it will be warm in the day and cool in the evenings.
Take a look at how September is compared to other months in Helsinki:
Water temperature in Helsinki in September
Water in Helsinki in September is Cold. It varies from +34°F to +67°F, with an average of +51°F.This is almost similar to the air temperature, which averages +57°F.
The water temperature in September is one of the warmest of the entire year:
The warmest water temperatures in Helsinki are reached in August, when the average sea temperature rises to +55°F. The coldest water temperatures are in February, with an average of +31°F.
Can you swim in Helsinki in September?
We would not recommend swimming in Helsinki in September, the water is very cold (+51°F on average). Consider swimming only if you are an experienced cold-water swimmer with proper gear.
🦭
Cold
Below +61°F
🏄♂️
Fresh
61°F - 70°F
🏊
Comfortable
70°F - 77°F
👙
Warm
77°F - 82°F
🔥
Very warm
+82°C and up
You will need a full-body wetsuit, cap, gloves, a warm change of clothes, and a hot drink ready for after your swim.
Climate in Helsinki in September
Helsinki weather looks like this, on average, in September and the surrounding months.
August
September
October
Avg. temperature
+66°F
+57°F
+48°F
Min. temperature
+37°F
+32°F
+18°F
Max. temperature
+84°F
+72°F
+64°F
Rainfall
83 mm
78 mm
83 mm
Wind
3 m/s
4 m/s
4 m/s
Avg. water temperature
+55°F
+51°F
+44°F
Humidity
76%
81%
84%
Air pressure
1011 HPa
1011 HPa
1011 HPa
Sunny days
8
5
4
Cloudy days
5
8
8
Rainy days
15
16
17
Snowy days
0
0
2
September weather is still as ok as in August.It’s getting colder in September. From +66°F in the day, the average maximum temperature lowers to +57°F.As September arrives, the amount of rainfall goes down. On average, the rainfall volume decreases from 83 mm to 78 mm.Humidity rises from 76% to 81%.Winds are stronger in comparison to August, going up from 3 m/s to 4 m/s on average.The days becoming less sunny, going from 8 sunny days in August to 5 in September.
October brings much the same weather, it remains ok.
Wind speed in Helsinki in September based on historical data.
Last Year
Historical Data
The average wind speed is 6 m/s getting up to 11 m/s which is a medium breeze. You can feel it, especially getting out of the water.
The average wind speed in Helsinki is gradually increasing during September, going from 5 m/s to 9 m/s over the course of the month.
Rain
Amount of rainfall in mm during September in Helsinki based on historical data.
Last Year
Historical Data
A chance of rain on a typical day in September stands at 60%, leading to total precipitation of around 160 mm. The maximum amount of rainfall per day is around 41 mm, which is moderate rain.September is a pretty wet month with over 18 rainy days, so don’t forget to pack an umbrella, raincoat, and a pair of wellies.
September is one of the rainiest months in Helsinki, here is a comparison with other months, total mm:
Helsinki wettest month is October, where a typical day has a 55% chance of precipitation and 83 mm of rainfall per day. February, on the other hand, is the driest month with a mere 3% chance of precipitation and 10 mm of rainfall per day.
How was the weather last September in Helsinki?
This is the weather in Helsinki in September 2023:
1 September
🌧️
+66°F
2 September
☀️
+62°F
3 September
☀️
+65°F
4 September
☁️
+68°F
5 September
☁️
+67°F
6 September
☀️
+64°F
7 September
☀️
+65°F
8 September
☁️
+68°F
9 September
☁️
+66°F
10 September
☁️
+69°F
11 September
🌫️
+67°F
12 September
🌫️
+66°F
13 September
🌧️
+65°F
14 September
☀️
+63°F
15 September
☀️
+63°F
16 September
🌧️
+65°F
17 September
☀️
+60°F
18 September
☀️
+58°F
19 September
☁️
+63°F
20 September
🌧️
+62°F
21 September
☁️
+67°F
22 September
☀️
+69°F
23 September
🌧️
+66°F
24 September
☀️
+63°F
25 September
☀️
+62°F
26 September
☀️
+63°F
27 September
☁️
+62°F
28 September
☀️
+64°F
29 September
☁️
+63°F
30 September
🌧️
+62°F
In September 2023 Helsinki had 13 sunny days, 9 cloudy days, and 6 rainy days. The average maximum temperature was +64°F, with an absolute maximum of +70°F and a minimum of +59°F. The average humidity was 88%, with a maximum of 100% and a minimum of 53%. The average wind speed was 6 m/s, with a maximum of 19 m/s and a minimum of 0 m/s.
Are you planning a trip in September?
Climate Change Over the Years
This is how Helsinki climate has changed over the last 43 years.
The climate in Helsinki in September has not changed that much over the last 43 years.
The average temperature was the lowest in 1987 (+41°F) and the highest in 2020 (+52°F). The driest year was 2002 with only 248 mm of rainfall, and the wettest year was 2020 with 1153 mm.
FAQ
Frequently asked questions about the weather in Helsinki in September:
Is September a good time to visit Helsinki?
It’s always a good time to visit Helsinki, but the weather is changeable in September, so plan a mix of indoor and outdoor activities and exploring, and pack for every eventuality.
Can you sunbathe in Helsinki in September?
September has mild temperatures in Helsinki. Not ideal for sunbathing, but still good for daytime outdoor activities, but plan for cool evenings. Pack a light jacket and shorts!
Can you swim in Helsinki in September?
Swimming in Helsinki in September is challenging and not recommended for inexperienced swimmers or without proper equipment and preparation.
Is Helsinki rainy in September?
Helsinki is often rainy in September. You may get a bit damp when outside, so pack an umbrella, and maybe even a raincoat.
Is it sunny in Helsinki in September?
Usually, it’s not very sunny in Helsinki in September, often it’s pretty cloudy. Pack for any eventuality; layering can help reduce the number of bulky items needed.
Other cities in Finland
Check out the weather for other cities in Finland.
For this page, we’ve looked at the typical weather in Helsinki, based on historical hourly weather data from January 1, 1979, to December 31, 2023.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.
