Weather in Oulu in September 2025
Average weather
Average temperature in Oulu in September
The expected average maximum temperature in September is +16°C with a maximum of +22°C and a minimum of +1°C.
The average maximum temperature goes down 14% by the end of the month, compared with the beginning of the month, from +18°C to +15°C.
Is Oulu warm or cold in September?
Oulu is typically mild in September.
Maximum temperatures go down compared to the previous month from +17°C to +12°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 Oulu:
Water temperature in Oulu in September
Water in Oulu in September is Cold. It varies from +9°C to +16°C, with an average of +13°C. Note that the air temperature is lower than the water temperature, averaging around +12°C.
The water temperature in September is one of the warmest of the entire year:
Can you swim in Oulu in September?
Climate in Oulu in September
| August | September | October | ||||
|---|---|---|---|---|---|---|
| Avg. temperature | ||||||
| +17°C | +12°C | +5°C | ||||
| Min. temperature | ||||||
| +2°C | -3°C | -17°C | ||||
| Max. temperature | ||||||
| +29°C | +24°C | +20°C | ||||
| Rainfall | ||||||
| 77 mm | 59 mm | 47 mm | ||||
| Wind | ||||||
| 3 m/s | 3 m/s | 4 m/s | ||||
| Avg. water temperature | ||||||
| +16°C | +13°C | +8°C | ||||
| Humidity | ||||||
| 78% | 82% | 86% | ||||
| Air pressure | ||||||
| 1010 HPa | 1010 HPa | 1009 HPa | ||||
| Sunny days | ||||||
| 4 | 3 | 3 | ||||
| Cloudy days | ||||||
| 9 | 10 | 12 | ||||
| Rainy days | ||||||
| 17 | 16 | 12 | ||||
| Snowy days | ||||||
| 0 | 0 | 5 | ||||
September weather is still as ok as in August. It’s getting colder in September. From +17°C in the day, the average maximum temperature lowers to +12°C. As September arrives, the amount of rainfall goes down. On average, the rainfall volume decreases from 77 mm to 59 mm. Humidity rises from 78% to 82%. The average wind speed doesn’t change much during September, staying around 3 m/s. The days becoming less sunny, going from 4 sunny days in August to 3 in September.
Next month (October) brings a further decline in the weather.
Wind
The average wind speed is 3 m/s getting up to 5 m/s which is a light breeze; barely moving the tree leaves.
The average wind speed in Oulu is gradually increasing during September, going from 2 m/s to 2 m/s over the course of the month.
Rain
How was the weather last September in Oulu?
Climate Change over Years
The climate in Oulu in September has not changed much over the last 43 years.
The average temperature was the lowest in 1985 (+3°C) and the highest in 2020 (+8°C). The driest year was 2002 with only 247 mm of rainfall, and the wettest year was 2021 with 603 mm.
FAQ
Is September a good time to visit Oulu?
Can you sunbathe in Oulu in September?
Can you swim in Oulu in September?
Is Oulu rainy in September?
Is it sunny in Oulu in September?
Other cities in Finland
Monthly weather in Oulu
Source of the data
For this page, we’ve looked at the typical weather in Oulu, 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.