South Ostrobothnia (Lappajärvi)
September
Weather in South Ostrobothnia for September 2026
Your guide to South Ostrobothnia weather in September - trends and predictions
Until now, September 2026 in South Ostrobothnia is cooler than usual, with temperatures averaging 15 °C, this is 2.2 °C below the typical seasonal average.
The forecast for the next days in South Ostrobothnia predicts temperatures to be around 14 °C, close to the historical average.
In general, the average temperature in South Ostrobothnia at the beginning of September is 19.9 °C. As the month progressed, temperatures tended to significantly cool down, reaching an average of 13.4 °C by the end of September.
South Ostrobothnia in September brings notable rainfall, with an average of 16 rainy days and a total precipitation of 74.5 mm.
Temperatures
Rain 🌧️
14
Dry days
16
Rainy days
0
Snow days
17°/9°
Temperatures
15 km/h
Avg max wind
79 %
Avg humidity
South Ostrobothnia Weather September
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Temperatures trend during September in South Ostrobothnia
See the weather trend as well as the moving average line
September weather in South Ostrobothnia day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| 1 Sept. |  Fog | 18° /10° | 2 mm | 3 | |
| 2 Sept. | Mist | 20° /9° | 0.6 mm | 4 | |
| 3 Sept. |  Patchy rain possible | 18° /10° | 3.6 mm | 3 | |
| 4 Sept. |  Sunny | 21° /9° | 0.3 mm | 4 | |
| 5 Sept. | Patchy rain possible | 21° /11° | 0.5 mm | 4 | |
| 6 Sept. | Sunny | 20° /10° | 0 mm | 5 | |
| 7 Sept. | Sunny | 21° /9° | 4.3 mm | 4 | |
| 8 Sept. | Patchy rain possible | 20° /12° | 2.8 mm | 3 | |
| 9 Sept. |  Partly cloudy | 19° /12° | 6 mm | 4 | |
| 10 Sept. |  Overcast | 19° /11° | 4 mm | 4 | |
| 11 Sept. |  Heavy rain at times | 19° /10° | 2.3 mm | 4 | |
| 12 Sept. | Heavy rain at times | 17° /10° | 2.1 mm | 3 | |
| 13 Sept. | Overcast | 16° /9° | 0.9 mm | 3 | |
| 14 Sept. | Patchy rain possible | 15° /7° | 1.1 mm | 3 | |
| 15 Sept. | Patchy rain possible | 15° /6° | 4.6 mm | 2 | |
| 16 Sept. | Sunny | 16° /8° | 3.2 mm | 3 | |
| 17 Sept. | Patchy rain possible | 15° /9° | 5.6 mm | 2 | |
| 18 Sept. | Partly cloudy | 15° /7° | 1.8 mm | 3 | |
| 19 Sept. | Sunny | 17° /8° | 1.4 mm | 3 | |
| 20 Sept. | Overcast | 15° /7° | 3 mm | 3 | |
| 21 Sept. |  Cloudy | 14° /5° | 1.8 mm | 3 | |
| 22 Sept. | Overcast | 12° /4° | 2.7 mm | 2 | |
| 23 Sept. |  Moderate or heavy rain shower | 12° /4° | 7.3 mm | 2 | |
| 24 Sept. | Moderate or heavy rain shower | 13° /5° | 1.3 mm | 4 | |
| 25 Sept. | Fog | 15° /7° | 0.1 mm | 1.4 | |
| 26 Sept. | Patchy rain possible | 12° /9° | 0.9 mm | 0.5 | |
| 27 Sept. | Overcast | 11° /9° | 0.7 mm | 1.2 | |
| 28 Sept. | Sunny | 15° /6° | 0 mm | 4 | |
| 29 Sept. | Mist | 15° /10° | 2 mm | 4 | |
| 30 Sept. | Mist | 13° /11° | 0 mm | 3 | |
| Next | |||||
Important Notice
Our weather forecast for South Ostrobothnia in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the South Ostrobothnia forecast closer to your planned date for the most up-to-date weather information.
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South Ostrobothnia in September - FAQ
What are the expected maximum and minimum temperatures in South Ostrobothnia during September?
Enjoy moderate daytime temperatures of up to 17° and cooler nights around 9°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in South Ostrobothnia during September?
Moderate rainfall is anticipated in South Ostrobothnia during September, with a total of 74.5 mm spread over approximately 16 days. Considering plans for rainy days is advisable.
What are the typical wind conditions in South Ostrobothnia during September?
The average wind speed in South Ostrobothnia during September is 15 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in South Ostrobothnia
Explore the daily rainfall trends and prepare for South Ostrobothnias September weather 💧
Typically, South Ostrobothnia has 16 rainy days in September with a total of 74.5 mm of rainfall.
UV exposure in South Ostrobothnia during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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