Helsinki
September
Weather in Helsinki for September 2025
Your guide to Helsinki weather in September - trends and predictions
In general, the average temperature in Helsinki at the beginning of September is 18.7 °C. As the month progressed, temperatures tended to significantly cool down, reaching an average of 15.4 °C by the end of September.
The climate of Helsinki in September is notably wet, with an average of 13 rainy days.
Is September a good time to visit Helsinki? check out the best time to travel to Helsinki page.
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17
Dry days
13
Rainy days
0
Snow days
17°/12°
Temperatures
21 km/h
Avg max wind
83 %
Avg humidity
Helsinki in September average weather
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| Mon. | Tue. | Wed. | Thu. | Fri. | Sat. | Sun. |
|---|---|---|---|---|---|---|
| 1  17° | 2 17° | 3 19° | 4  20° | 5 21° | 6  18° | 7  19° |
| 8 20° | 9  20° | 10 20° | 11 19° | 12 19° | 13  18° | 14 17° |
| 15 16° | 16 18° | 17 18° | 18 15° | 19 19° | 20 18° | 21 17° |
| 22 15° | 23 15° | 24 17° | 25 16° | 26 16° | 27 16° | 28  16° |
| 29 14° | 30 13° |
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Temperatures trend during September in Helsinki
See the weather trend as well as the moving average line
September weather day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| 1 Sept. | Light rain shower | 17° /12° | 4.3 mm | 4 | |
| 2 Sept. | Light rain shower | 17° /12° | 7.4 mm | 4 | |
| 3 Sept. | Light rain shower | 19° /13° | 1.4 mm | 5 | |
| 4 Sept. | Cloudy | 20° /13° | 0 mm | 5 | |
| 5 Sept. | Patchy rain possible | 21° /13° | 0.3 mm | 5 | |
| 6 Sept. | Sunny | 18° /12° | 0 mm | 6 | |
| 7 Sept. | Partly cloudy | 19° /11° | 0 mm | 6 | |
| 8 Sept. | Cloudy | 20° /14° | 0 mm | 5 | |
| 9 Sept. | Overcast | 20° /14° | 0 mm | 5 | |
| 10 Sept. | Cloudy | 20° /14° | 1.2 mm | 5 | |
| 11 Sept. | Sunny | 19° /14° | 4.8 mm | 5 | |
| 12 Sept. | Sunny | 19° /14° | 0.1 mm | 5 | |
| 13 Sept. | Moderate rain | 18° /13° | 17 mm | 4 | |
| 14 Sept. | Overcast | 17° /11° | 11.1 mm | 4 | |
| 15 Sept. | Overcast | 16° /10° | 1.4 mm | 4 | |
| 16 Sept. | Overcast | 18° /11° | 0 mm | 4 | |
| 17 Sept. | Light rain shower | 18° /10° | 0.9 mm | 5 | |
| 18 Sept. | Overcast | 15° /8° | 0 mm | 4 | |
| 19 Sept. | Light rain shower | 19° /11° | 0.9 mm | 5 | |
| 20 Sept. | Light rain shower | 18° /11° | 1.6 mm | 5 | |
| 21 Sept. | Patchy rain possible | 17° /11° | 0 mm | 5 | |
| 22 Sept. | Sunny | 15° /10° | 0 mm | 5 | |
| 23 Sept. | Light rain shower | 15° /10° | 5.3 mm | 4 | |
| 24 Sept. | Patchy rain possible | 17° /12° | 0.6 mm | 5 | |
| 25 Sept. | Overcast | 16° /11° | 1.5 mm | 4 | |
| 26 Sept. | Patchy rain possible | 16° /12° | 10.1 mm | 4 | |
| 27 Sept. | Patchy rain possible | 16° /12° | 8.8 mm | 4 | |
| 28 Sept. | Mist | 16° /10° | 11.7 mm | 4 | |
| 29 Sept. | Partly cloudy | 14° /9° | 0.3 mm | 4 | |
| 30 Sept. | Light rain shower | 13° /8° | 1.7 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.
Helsinki in September - FAQ
What are the expected maximum and minimum temperatures in Helsinki during September?
Enjoy moderate daytime temperatures of up to 17° and cooler nights around 12°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Helsinki during September?
Moderate rainfall is anticipated in Helsinki during September, with a total of 75.3 mm spread over approximately 13 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 21 km/h, suggesting breezy to windy conditions, depending on your activities.
What to pack to Helsinki in September?
As you prepare for your trip to Helsinki in September, it's important to consider the typical weather patterns for the time of year. Below is a carefully tailored packing list to ensure that your time in Helsinki, during September, is comfortable and enjoyable, regardless of the weather conditions.
- Clothing
- Warm Clothing: Sweaters, hoodies, long pants
- Rain Gear: Lightweight, waterproof clothing
- Footwear
- Waterproof Shoes
- Accessories
- Scarves: To protect you from the cold wind
- Gloves/Mittens: Essential for cold weather
- Warm Hats: Warm hats for insulation in cold weather
- Umbrellas/Raincoats: For rainy days
September rainfall patterns in Helsinki
Explore the daily rainfall trends and prepare for Helsinkis September weather 💧
UV exposure in Helsinki during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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