Helsinki
September
Weather in Helsinki for September 2025
Your guide to Helsinki weather in September - trends and predictions
Wind Warning for Land Areas - See hour by hour.
So far, September 2025 in Helsinki is slightly warmer than the historical average by 1.3 °C.
The forecast for the next days in Helsinki predicts a temperature of 13.2 °C, which is cooler than the historical average.
In general, the average temperature in Helsinki at the beginning of September is 17 °C. As the month progressed, temperatures tended to significantly cool down, reaching an average of 11.3 °C by the end of September.
Helsinki in September brings notable rainfall, with an average of 17 rainy days and a total precipitation of 64.1 mm.
Official Weather Alert ⚠️
Temperatures
Rain 🌧️
13
Dry days
17
Rainy days
0
Snow days
15°/9°
Temperatures
18 km/h
Avg max wind
77 %
Avg humidity
Helsinki Weather September
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Temperatures trend during September in Helsinki
See the weather trend as well as the moving average line
September weather in Helsinki day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| 1 Sept. |  Patchy rain possible | 16° /10° | 1.8 mm | 4 | |
| 2 Sept. | Patchy rain possible | 15° /9° | 3.3 mm | 4 | |
| 3 Sept. | Patchy rain possible | 17° /10° | 0.8 mm | 4 | |
| 4 Sept. |  Partly cloudy | 17° /9° | 0 mm | 5 | |
| 5 Sept. |  Sunny | 18° /10° | 0.1 mm | 4 | |
| 6 Sept. |  Overcast | 18° /10° | 0.3 mm | 5 | |
| 7 Sept. | Overcast | 18° /10° | 0.1 mm | 5 | |
| 8 Sept. |  Cloudy | 19° /11° | 0.1 mm | 5 | |
| 9 Sept. | Overcast | 19° /12° | 0.2 mm | 5 | |
| 10 Sept. | Partly cloudy | 18° /12° | 0.5 mm | 4 | |
| 11 Sept. | Patchy rain possible | 19° /12° | 2.1 mm | 5 | |
| 12 Sept. |  Moderate rain at times | 17° /12° | 1.1 mm | 4 | |
| 13 Sept. |  Moderate rain | 17° /11° | 8.8 mm | 4 | |
| 14 Sept. | Partly cloudy | 15° /10° | 7.5 mm | 4 | |
| 15 Sept. | Overcast | 14° /8° | 2.9 mm | 4 | |
| 16 Sept. | Patchy rain possible | 16° /13° | 4.5 mm | 0.4 | |
| 17 Sept. | Moderate rain | 15° /12° | 16.1 mm | 0.5 | |
| 18 Sept. | Patchy rain possible | 16° /10° | 1.8 mm | 0.6 | |
| 19 Sept. | Patchy rain possible | 16° /10° | 2.1 mm | 0.7 | |
| 20 Sept. | Patchy rain possible | 16° /10° | 0.3 mm | 3 | |
| 21 Sept. | Patchy rain possible | 13° /11° | 0.8 mm | 3 | |
| 22 Sept. | Patchy rain possible | 15° /10° | 1.9 mm | 3 | |
| 23 Sept. | Patchy rain possible | 11° /6° | 0.1 mm | 2 | |
| 24 Sept. | Patchy rain possible | 11° /5° | 1.5 mm | 2 | |
| 25 Sept. | Patchy rain possible | 12° /9° | 2.7 mm | 3 | |
| 26 Sept. | Patchy rain possible | 8° /5° | 0.4 mm | 2 | |
| 27 Sept. | Sunny | 10° /4° | 0 mm | 3 | |
| 28 Sept. | Cloudy | 12° /4° | 0 mm | 2 | |
| 29 Sept. | Patchy rain possible | 14° /11° | 0.3 mm | 3 | |
| 30 Sept. | Partly cloudy | 12° /7° | 1.4 mm | 4 | |
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Important Notice
Our weather forecast for Helsinki 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 Helsinki forecast closer to your planned date for the most up-to-date weather information.
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Helsinki in September - FAQ
What are the expected maximum and minimum temperatures in Helsinki during September?
During September, expect a variety of temperatures with highs around 15° and lows near 9°, suitable for diverse activities and preferences.
How much rainfall should be expected in Helsinki during September?
Moderate rainfall is anticipated in Helsinki during September, with a total of 64.1 mm spread over approximately 17 days. Considering plans for rainy days is advisable.
What are the typical wind conditions in Helsinki during September?
The average wind speed in Helsinki during September is 18 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Helsinki
Explore the daily rainfall trends and prepare for Helsinkis September weather 💧
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