Last updated: August 21, 2025
September in Turku, Finland offers a fascinating transition from summer's warmth to autumn's embrace. With maximum temperatures reaching up to 23°C (74°F) and an average of 12°C (54°F), the weather invites outdoor exploration. However, cooler nights can dip down to a brisk -3°C (28°F), reminding us of the impending change in seasons. This month also sees 69 mm (2.7 in) of precipitation spread over 12 days, contributing to the region's lush landscape. High humidity levels of 86% often create a refreshing feel, making September a uniquely crisp and vibrant time to experience Turku's natural beauty.
As September unfolds in Turku, Finland, the city transitions into the welcoming embrace of early autumn. With minimal temperatures dipping to -3°C (28°F) and a pleasant average of 12°C (54°F), residents and visitors alike can enjoy the crisp air and muffled sounds of nature preparing for winter. The maximum temperature reaching a comfortable 23°C (74°F) allows for delightful outdoor activities as summer's warmth lingers just a bit longer. This month marks a distinct turning point, as the days grow shorter and the coolness of fall hints at the colder months ahead, creating a unique blend of seasonal beauty that captivates all who experience it.
In September, Turku experiences a notable shift in precipitation patterns, with a total of 69 mm (2.7 in) of rain spread over 12 days. This marks a drop from the soggy summer months, where August recorded a hefty 95 mm (3.7 in) over 13 days. As the city transitions into autumn, the rainfall becomes more consistent, suggesting a steadier rhythm of precipitation rather than the intense summer showers. This higher frequency of rainy days, combined with the substantial rainfall, indicates that fall has officially arrived in Turku, setting the stage for the chillier months ahead.
In September, Turku experiences a notable shift in humidity levels, with an average of 86% that comfortably bridges the gap between the summer months and the onset of autumn. This elevated humidity is a slight increase from the preceding August (79%), showcasing a gradual return to the higher moisture levels reminiscent of the winter months. As the year progresses, humidity remains consistently high, peaking in January at 92% and gradually tapering off to approximately 77% in May. September's humidity level signals the start of a wetter season, as the city prepares for the colder months ahead where averages in October and November rebound to 90% and 91% respectively, reinforcing Turku's characteristic damp climate.
As September arrives in Turku, Finland, the UV Index drops to a moderate level of 4, maintaining the trend set in the preceding months of summer. This aligns with the gradual decline from the high UV readings of July and June, both at 7, which demanded more caution during outdoor activities due to their 25-minute burn time. In contrast, September’s 30-minute burn time allows for safer sun exposure while still enough to enjoy the crisp early autumn days. This seasonal transition showcases nature’s rhythm, as the sun’s intensity eases before the colder months approach, where the UV Index will further dip to low levels by October. For ongoing updates on UV levels and precautions in Turku, visit Turku UV Index.
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September in Turku, Finland, brings a delightful blend of fading summer and the onset of autumn, with 313 hours of sunshine brightening the days. As the warmth of summer recedes, this month stands out as a significant decline from the peak 495 hours in June, yet still offers more sunlight than the upcoming months, such as October's 209 hours and November's mere 126 hours. The trend shows a gradual tapering from the vibrant summer light, culminating in a cozy, golden ambiance that marks the transition into fall. September serves as a gentle reminder of the sunny days past, while inviting the crispness of autumn to embrace the landscape of Turku.
In Turku, Finland, September brings a 31% chance of sunny weather, aligning with the trend of late summer transitioning into autumn. As temperatures begin to cool after the vibrant warmth of July and June—when the sun shines over half the days—September's likelihood of sunshine mirrors August's, suggesting a gradual decline in sunny moments. This month, however, serves as a pivot point, foreshadowing the upcoming months where sunny days drop significantly, resting below 25% by October. So while September may not promise endless sunshine, it offers a final flourish of clearer skies before winter's embrace.
In September, Turku, Finland experiences a notable transition in daylight, with approximately 12 hours of sunlight illuminating the city. This marks a gradual decline from the long, sun-soaked days of summer, where daylight peaked at 18 hours in June and July. As autumn approaches, daylight begins to wane, yet September still offers a generous amount of sunlight compared to the winter months. The shift signifies a gentle transition into the darker season, bridging the vibrant warmth of late summer toward the cooler, crisper days of fall, while hinting at the shorter daylight hours that will characterize the coming months.
As September sweeps into Turku, Finland, the winds begin to dance with a gentle yet consistent average speed of 3.5 m/s (8 mph). This month's breezes mirror the mild conditions of late summer, slightly nudging up from August's calm 3.6 m/s (8 mph). Interestingly, September's winds stand out as they bridge the transition towards the more blustery autumn months, with October promising a noticeable increase to 4.5 m/s (10 mph). This gradual uptick in wind speeds reflects the changing seasons, hinting at the invigorating gusts that will soon herald the deepening chill of fall. Overall, September offers a delightful blend of lingering warmth and fresh, refreshing air, setting the stage for the vibrant shifts in weather to come.
Weather in Turku varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Turku, focusing on differences in temperature, rainfall, humidity, and UV levels.
In September, temperatures in Turku range from a brisk minimum of -3°C (28°F) to a comfortable maximum of 23°C (74°F), presenting an average of 12°C (54°F). The month sees about 69 mm (2.7 in) of precipitation over 12 days, accompanied by high humidity at 86%. In stark contrast, January brings frigid conditions, with temperatures plummeting to a minimum of -25°C (-13°F) and a maximum of only 8°C (47°F), resulting in an average temperature of -2°C (28°F). Precipitation is less frequent in January, totaling 48 mm (1.9 in) across just 9 days, but humidity remains high at 92%. For a more detailed look at January weather, you can visit Turku weather in January.
September and February present stark contrasts in weather conditions. In September, temperatures range from a minimum of -3°C (28°F) to a comfortable maximum of 23°C (74°F), with an average temperature of 12°C (54°F). The month experiences 69 mm (2.7 inches) of precipitation over 12 days, coupled with a high humidity level of 86%. In contrast, February is much harsher, with temperatures plummeting to a minimum of -24°C (-11°F) and only reaching a maximum of 7°C (45°F), resulting in an average temperature of -3°C (26°F). Precipitation is lower, at 42 mm (1.7 inches) over just 8 days, but the humidity remains high at 90%. For more detailed insights on February weather, you can check Turku weather in February.
September and March present contrasting weather patterns. In September, temperatures range from a minimum of -3°C (28°F) to a pleasant maximum of 23°C (74°F), with an average of 12°C (54°F). The month experiences 69 mm (2.7 in) of precipitation over about 12 days, and the humidity is relatively high at 86%. In stark contrast, March sees much colder conditions with temperatures dipping as low as -25°C (-12°F) and peaking at only 13°C (55°F), yielding an average temperature of 0°C (31°F). Precipitation is lower at 45 mm (1.8 in) across 10 days, with humidity reaching 89%. For a detailed look at the weather in March, you can visit Turku weather in March.
In September, the weather shows a mild transition towards autumn, with temperatures that range from a chilly -3°C (28°F) at night to a pleasant high of 23°C (74°F) during the day, averaging around 12°C (54°F). This month experiences about 69 mm (2.7 in) of precipitation over 12 days, with humidity levels at a high 86%. In contrast, April still feels quite wintry, boasting lower temperatures that dip to -12°C (10°F) at night and rise to a maximum of 21°C (71°F), with an average temperature of only 4°C (40°F). Precipitation is lighter in April, totaling 34 mm (1.3 in) across 9 days, and the humidity remains similar at 85%. For more detailed insights, you can explore Turku weather in April.
When comparing the weather in September and May, we see notable differences in temperature and precipitation. September experiences milder temperatures with an average of 12°C (54°F) and a maximum of 23°C (74°F), while May has a slightly lower average of 10°C (50°F) and can peak at 28°C (83°F). Additionally, September tends to be wetter, with 69 mm (2.7 in) of precipitation over 12 days, compared to May's 48 mm (1.9 in) over 10 days. Humidity levels are also higher in September at 86%, compared to May's 77%. For more detailed insights, check out Turku weather in May.
September weather contrasts notably with June, showcasing a shift towards cooler temperatures and increased precipitation. In September, temperatures range from a minimum of -3°C (28°F) to a maximum of 23°C (74°F), averaging around 12°C (54°F), compared to June's warmer temperatures, which span from 2°C (36°F) to 30°C (86°F) with an average of 16°C (61°F). Additionally, September experiences more rainy days, totaling 12 days with 69 mm (2.7 in) of precipitation, in contrast to June's 7 days and 45 mm (1.8 in). The humidity in September is also higher at 86%, compared to June's 78%, contributing to the overall feeling of chill in the air during the fall month. For more details on June weather, you can visit Turku weather in June.
When comparing the weather in September to July, we see notable differences in temperature and humidity. September experiences cooler temperatures with a minimum of -3°C (28°F) and an average of 12°C (54°F), while July boasts much warmer conditions, featuring a minimum of 5°C (40°F) and an average of 18°C (64°F). The maximum temperature in July reaches a sunny 33°C (91°F), contrasting sharply with September's maximum of 23°C (74°F). Additionally, September has higher humidity at 86% compared to July's 78%, making the former feel more damp. Precipitation levels are also noteworthy, with September receiving 69 mm (2.7 in) over 12 days, while July sees slightly more with 85 mm (3.4 in) over 11 days. For those interested in detailed July specifics, check out Turku weather in July.
September experiences cooler temperatures compared to August, with minimums dropping to -3°C (28°F) and an average of 12°C (54°F), while August boasts milder temperatures with a minimum of 4°C (40°F) and an average of 16°C (62°F). The maximum temperatures also reflect this trend, reaching up to 23°C (74°F) in September compared to 29°C (84°F) in August. In terms of precipitation, September receives 69 mm (2.7 in) over 12 days, slightly less than August’s 95 mm (3.7 in) across 13 days, despite September's higher humidity at 86% versus August’s 79%. For a more detailed look at August conditions, you can visit Turku weather in August.
In September, the weather tends to be milder, with average temperatures ranging from a low of -3°C (28°F) to a high of 23°C (74°F). This month receives approximately 69 mm (2.7 in) of precipitation over 12 days, and humidity sits at a comfortable 86%. By October, the chill sets in more profoundly, as temperatures decrease further, with averages between -6°C (21°F) and a maximum of 17°C (63°F). Precipitation increases slightly to 78 mm (3.1 in), spread over 15 days, and humidity rises to 90%, contributing to a cooler, wetter atmosphere. For a more detailed look at the October weather in Turku, check out Turku weather in October.
September generally offers more mild temperatures compared to November, with average daytime highs reaching 23°C (74°F) and a minimum that rarely drops below -3°C (28°F). In contrast, November sees a significant drop, with average temperatures hovering around 3°C (38°F) and nighttime lows plummeting to -9°C (15°F). While both months experience precipitation, September sees slightly more rainfall (69 mm) over 12 days, whereas November has 54 mm over 10 days. Additionally, humidity levels rise in November to 91%, slightly higher than September's 86%. For more details on November conditions, you can check Turku weather in November.
In September, the weather is relatively mild with temperatures ranging from a chilly -3°C (28°F) at night to a comfortable 23°C (74°F) during the day, averaging around 12°C (54°F). The month experiences approximately 69 mm (2.7 in) of precipitation over about 12 days, with humidity levels at 86%. In contrast, December brings much colder conditions, with temperatures dropping significantly to a minimum of -21°C (-5°F) and a maximum of only 7°C (45°F), averaging around 0°C (31°F). Precipitation increases slightly to 74 mm (2.9 in) over 14 days, and humidity rises to 89%. For a detailed look at December weather, you can visit Turku weather in December.
As summer transitions to autumn, September in Turku showcases a remarkable shift in weather patterns. The cooler temperatures offer a refreshing reprieve from the warmer months, with average temperatures hovering around 12°C, making it a perfect time for outdoor exploration. While you may experience a couple of brisk days near freezing, the occasional peak at 23°C provides a nostalgic reminder of the summer sun. Notably, this month also witnesses increased precipitation, with rain making an appearance on about 12 days, contributing to a higher humidity level of 86%. This blend of cooler air and moisture prepares the landscape for the vibrant fall foliage ahead. To learn more about what to expect throughout the year, check out Turku Climate.