Weather in Vaasa in September 2025
Average weather
Average temperature in Vaasa in September
Going from a maximum of +22°C during the day to a minimum of +1°C during the night, the temperature in September averages around +16°C.
The average maximum temperature goes down 19% by the end of the month, compared with the beginning of the month, from +17°C to +13°C.
Is Vaasa warm or cold in September?
Vaasa is typically mild in September.
Maximum temperatures go down compared to the previous month from +18°C to +13°C. The minimum temperature also goes down from +11°C to +7°C.
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 +9°C to +17°C, with an average of +13°C. This is almost similar to the air temperature, which averages +13°C.
The water temperature in September is one of the warmest of the entire year:
Can you swim in Vaasa in September?
Climate in Vaasa in September
| August | September | October | ||||
|---|---|---|---|---|---|---|
| Avg. temperature | ||||||
| +18°C | +13°C | +7°C | ||||
| Min. temperature | ||||||
| +2°C | -3°C | -16°C | ||||
| Max. temperature | ||||||
| +30°C | +25°C | +18°C | ||||
| Rainfall | ||||||
| 82 mm | 69 mm | 56 mm | ||||
| Wind | ||||||
| 2 m/s | 3 m/s | 3 m/s | ||||
| Avg. water temperature | ||||||
| +17°C | +13°C | +8°C | ||||
| Humidity | ||||||
| 78% | 82% | 85% | ||||
| Air pressure | ||||||
| 1010 HPa | 1010 HPa | 1009 HPa | ||||
| Sunny days | ||||||
| 5 | 4 | 3 | ||||
| Cloudy days | ||||||
| 8 | 10 | 12 | ||||
| Rainy days | ||||||
| 17 | 16 | 12 | ||||
| Snowy days | ||||||
| 0 | 0 | 3 | ||||
September weather is still as ok as in August. It’s getting colder in September. From +18°C in the day, the average maximum temperature lowers to +13°C. 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
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
How was the weather last September in Vaasa?
Climate Change over Years
The climate in Vaasa in September has not changed much over the last 43 years.
The average temperature was the lowest in 1985 (+4°C) and the highest in 2020 (+10°C). The driest year was 2002 with only 260 mm of rainfall, and the wettest year was 2019 with 2226 mm.
FAQ
Is September a good time to visit Vaasa?
Can you sunbathe in Vaasa in September?
Can you swim in Vaasa in September?
Is Vaasa rainy in September?
Is it sunny in Vaasa in September?
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.