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Vaasa in September: Weather, Average temperature and Climate

Discover the weather for Vaasa in September and if it’s a good time to travel (based on historical data).
Check flight prices to Vaasa on Avionero:
September

Weather in Vaasa in September 2025

OK Weather
Mild
🌧️
Rainy
🌊
Cold water
September could be a good time to visit Vaasa, as the weather is generally fine. The average high temperature is around +55°F, and there are typically 4 sunny days in September. However, expect about 16 rainy days, and total monthly rainfall of approximately 69 mm. The weather is changeable so pack for every eventuality. Search flights in one click on Avionero.

Average weather

☀️
+55°F
Avg. max. temperature
+27°F
Min.
+77°F
Max.
69 mm
Total precipitation
82%
Avg. humidity
3 m/s
Avg. wind
4 ☀️
Sunny Days
10 ⛅️
Cloudy
16 🌦
Rainy
Our opinion: Vaasa has OK weather in September.

Average temperature in Vaasa in September

Here are the expected maximum, average and minimum temperatures in Vaasa for September based on the historical data.
Last Year
Historical Data

The expected average maximum temperature in September is +61°F with a maximum of +72°F and a minimum of +34°F.

The average maximum temperature goes down 19% by the end of the month, compared with the beginning of the month, from +63°F to +55°F.

Is Vaasa warm or cold in September?

Vaasa is typically mild in September.

Maximum temperatures go down compared to the previous month from +64°F to +55°F. The minimum temperature also goes down from +52°F to +45°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 Vaasa:

Water temperature in Vaasa in September

Water in Vaasa in September is Cold. It varies from +48°F to +62°F, with an average of +55°F. This is almost similar to the air temperature, which averages +55°F.

The water temperature in September is one of the warmest of the entire year:

The warmest water temperatures in Vaasa are reached in August, when the average sea temperature rises to +62°F. The coldest water temperatures are in February, with an average of +31°F.

Can you swim in Vaasa in September?

We would not recommend swimming in Vaasa in September, the water is very cold (+55°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 Vaasa in September

Vaasa weather looks like this, on average, in September and the surrounding months.
AugustSeptemberOctober
Avg. temperature
+64°F+55°F+45°F
Min. temperature
+36°F+27°F+3°F
Max. temperature
+86°F+77°F+64°F
Rainfall
82 mm69 mm56 mm
Wind
2 m/s3 m/s3 m/s
Avg. water temperature
+62°F+55°F+47°F
Humidity
78%82%85%
Air pressure
1010 HPa1010 HPa1009 HPa
Sunny days
543
Cloudy days
81012
Rainy days
171612
Snowy days
003

September weather is still as ok as in August. It’s getting colder in September. From +64°F in the day, the average maximum temperature lowers to +55°F. As September arrives, the amount of rainfall goes down. On average, the rainfall volume decreases from 82 mm to 69 mm. Humidity rises from 78% to 82%. Winds are stronger in comparison to August, going up from 2 m/s to 3 m/s on average. The days becoming less sunny, going from 5 sunny days in August to 4 in September.

Next month (October) brings a further decline in the weather.

Wind

Wind speed in Vaasa in September based on historical data.
Last Year
Historical Data

The average wind speed is 4 m/s getting up to 7 m/s which is a medium breeze. You can feel it, especially getting out of the water.

The average wind speed in Vaasa is gradually increasing during September, going from 3 m/s to 3 m/s over the course of the month.

Rain

Amount of rainfall in mm during September in Vaasa based on historical data.
Last Year
Historical Data
Total precipitation in September is about 121 mm, with a 57% chance of rain on a typical day. The maximum amount of rainfall per day is around 23 mm, which is considered light rain. September is a pretty wet month with over 17 rainy days, so don’t forget to pack an umbrella, raincoat, and a pair of wellies.
September is one of the rainiest months in Vaasa, here is a comparison with other months, total mm:
Vaasa wettest month is August, where a typical day has a 55% chance of precipitation and 82 mm of rainfall per day. January, on the other hand, is the driest month with a mere 3% chance of precipitation and 6 mm of rainfall per day.

How was the weather last September in Vaasa?

This is the weather in Vaasa in September 2023:
1 September
☁️
+62°F
2 September
☁️
+65°F
3 September
☁️
+61°F
4 September
☀️
+63°F
5 September
☀️
+62°F
6 September
☀️
+60°F
7 September
☁️
+64°F
8 September
☀️
+68°F
9 September
☀️
+71°F
10 September
☁️
+64°F
11 September
☁️
+67°F
12 September
☁️
+64°F
13 September
☀️
+58°F
14 September
☁️
+55°F
15 September
☀️
+57°F
16 September
🌧️
+58°F
17 September
☀️
+56°F
18 September
☀️
+59°F
19 September
☀️
+61°F
20 September
🌧️
+58°F
21 September
☀️
+64°F
22 September
☀️
+72°F
23 September
☁️
+63°F
24 September
☀️
+59°F
25 September
☀️
+59°F
26 September
☁️
+60°F
27 September
☁️
+59°F
28 September
☀️
+59°F
29 September
☁️
+60°F
30 September
🌧️
+56°F
In September 2023 Vaasa had 15 sunny days, 12 cloudy days, and 3 rainy days. The average maximum temperature was +61°F, with an absolute maximum of +72°F and a minimum of +55°F. The average humidity was 87%, with a maximum of 100% and a minimum of 57%. The average wind speed was 4 m/s, with a maximum of 10 m/s and a minimum of 0 m/s.
Are you planning a trip in September?

Climate Change Over the Years

This is how Vaasa climate has changed over the last 43 years.

The climate in Vaasa in September has not changed that much over the last 43 years.

The average temperature was the lowest in 1985 (+40°F) and the highest in 2020 (+49°F). The driest year was 2002 with only 260 mm of rainfall, and the wettest year was 2019 with 2226 mm.

FAQ

Frequently asked questions about the weather in Vaasa in September:

Is September a good time to visit Vaasa?

It’s always a good time to visit Vaasa, 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 Vaasa in September?

September has mild temperatures in Vaasa. 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 Vaasa in September?

Swimming in Vaasa in September is challenging and not recommended for inexperienced swimmers or without proper equipment and preparation.

Is Vaasa rainy in September?

Vaasa 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 Vaasa in September?

Usually, it’s not very sunny in Vaasa 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.

Monthly weather in Vaasa

Source of the data

For this page, we’ve looked at the typical weather in Vaasa, 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.