Last updated: August 21, 2025
In September, Hanko, Finland experiences a shift towards cooler temperatures, with a maximum of 20°C (68°F) and a comfortable average of 14°C (57°F). As the month progresses, temperatures dip to a minimum of 7°C (45°F), creating a crisp atmosphere ideal for outdoor activities. However, expect some rain, as 71 mm (2.8 in) of precipitation falls over approximately 14 days of the month. The humidity is notably high at 87%, contributing to the fresh, invigorating feel of early autumn in this picturesque coastal town. Whether you're exploring the scenic landscapes or enjoying local festivities, September in Hanko offers a blend of refreshing weather and seasonal beauty.
As September rolls into Hanko, Finland, the transition from summer to autumn is palpable in the crisp air. The temperatures begin to cool, with minimums around 7°C (45°F), while averages settle at a comfortable 14°C (57°F), peaking at 20°C (68°F) during the day. This month reflects a gentle shift from the warmth of August, offering a delightful blend of pleasant days and cooler nights. It's a time when nature flaunts its early autumn colors, inviting both residents and visitors to embrace the scenic beauty and refreshing weather before winter's chill returns.
September in Hanko, Finland, brings a noticeable shift in precipitation patterns, marking a transitional phase as summer wanes. With 71 mm (2.8 in) of rain falling over 14 days, this month features a significant increase compared to the drier summer months. Following August's peak of 94 mm (3.7 in), September maintains a relatively high precipitation level, hinting at the advancing autumn. Notably, this trend indicates that Hanko's wet season is beginning to establish itself, as October intensifies further with 123 mm (4.8 in) and an increase in rainfall days. Overall, September serves as a bridge, where the lush greenery of late summer begins to give way to the crisp air of fall, accompanied by frequent showers that rejuvenate the landscape.
In September, Hanko, Finland, experiences a notable shift in humidity, maintaining a level of 87% which reflects a slight increase from the drier conditions of summer. After the milder humidity levels of July and August, September marks a transition back to richer moisture in the air as the autumn months approach. This gradual uptick is part of a broader trend where humidity remains consistently high throughout the fall, peaking in the colder months with January and February measuring at 92% and 91%, respectively. Overall, Hanko's climate showcases a strong seasonal influence, where the lingering warmth of summer gives way to the crisp, damp feel characteristic of Nordic autumns.
September in Hanko, Finland, shows a slight dip in UV intensity as summer edges toward autumn, with the UV Index sitting at 4, categorizing it as moderate. This means that while outdoor enthusiasts can still enjoy the lingering warmth, they should be mindful of their sun exposure, with a burn time of 30 minutes. Compared to the peak summer months of June and July, which both clocked in at a high 7, September offers a gentler sun, yet it’s wise to remember that protection is still essential. As the year progresses, the UV Index will continue to decline, landing at a more relaxed 2 in October. For a detailed look at the UV trends year-round, visit Hanko UV Index.
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In September, Hanko enjoys a delightful 319 hours of sunshine, marking a gentle transition from the vibrant summer months to the crisp autumn days. This decline is subtle, especially when compared to the peak of 490 hours in June, and it reflects the gradual shortening of days as the year progresses. While still a generous amount of sunlight, September's hours serve as a reminder of the approaching change, inviting residents and visitors alike to savor the golden rays before the diminishing light of October settles in with only 215 hours. The trends in Hanko's sunshine hours illustrate a charming dance with the seasons, where every month offers its own unique character, culminating in a cozy autumn feel.
September in Hanko, Finland, welcomes a moderate 31% chance of sunny weather, marking a shift from the peak summer months. As the intensity of sunlight starts to wane from the high of July at 61%, September offers a blend of warmth and cooler breezes, reminiscent of the changing season. This month, however, does not break away entirely from the sunny trends seen in the summer; though less promising than earlier in the year, it still provides opportunities to bask in the sun. The likelihood of clear skies continues to dip into autumn, but September remains a delightful time to enjoy the crisp air and fleeting warmth before the harsher months ahead.
As the summer fades in Hanko, Finland, September greets residents with a shift in daylight, offering about 12 hours of sunshine. This marks a gradual decline from the sun-drenched 18 hours experienced in June and 17 hours in July, creating a transition that gently ushers in the autumn months. While the daylight duration drops to 15 hours in August, September signifies a more pronounced decrease, reflecting the natural ebb of sunlight as winter approaches. Following this month, October will further lower daylight hours to 10—a reminder of the approaching darker seasons. The trends across the months highlight a compelling journey from summer's lingering brightness to the cozy embrace of fall, inviting both reflection and preparation for the colder days ahead.
As September arrives in Hanko, Finland, the winds begin to pick up, averaging 7.6 m/s (17 mph), slightly higher than the summer months. This subtle increase signals the transition into autumn, where the breeze becomes more invigorating. Interestingly, after a dip in wind speeds during June and July, September reflects a noticeable rise, maintaining momentum into October, which boasts an average of 9.3 m/s (21 mph). This trend not only enchants visitors with the crispness of the air but also hints at the approaching chill of winter, contrasting the calmer summer days that preceded it. As the leaves start to color and fall, the winds of September weave a tapestry of change, inviting both locals and travelers to experience the vibrant shifts of nature in this coastal haven.
Weather in Hanko varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Hanko, focusing on differences in temperature, rainfall, humidity, and UV levels.
September and January present contrasting weather conditions. In September, temperatures range from a mild 7°C (45°F) at night to a pleasant high of 20°C (68°F) during the day, accompanied by relatively high humidity at 87%. Despite being a wet month with 71 mm (2.8 in) of rainfall over about 14 days, the overall atmosphere remains quite temperate. In stark contrast, January experiences much colder conditions with nighttime lows plunging to -13°C (8°F) and daytime averages hovering around 1°C (33°F). This winter month sees less precipitation at 56 mm (2.2 in) but is characterized by a higher humidity of 92%. For a closer look at January weather specifics, visit Hanko weather in January.
September and February offer starkly contrasting weather experiences. In September, temperatures range from a mild minimum of 7°C (45°F) to a pleasant maximum of 20°C (68°F), with an average of 14°C (57°F). However, it sees significant precipitation of 71 mm (2.8 in) over 14 days, accompanied by high humidity at 87%. In contrast, February is much colder, with temperatures peaking at just 6°C (43°F) and dipping to a chilling minimum of -13°C (10°F), averaging around -1°C (31°F). Although it experiences less rainfall, with 49 mm (1.9 in) over 11 days, the humidity remains relatively high at 91%. This comparison highlights the shift from the mild, damp conditions of September to the frigid, snowy weather typical of February. For more detailed information on the weather in Hanko during February, you can visit Hanko weather in February.
September and March present markedly different weather conditions. In September, temperatures range from a minimum of 7°C (45°F) to a comfortable average of 14°C (57°F), peaking at 20°C (68°F). The month experiences 71 mm (2.8 in) of precipitation over approximately 14 days, with humidity levels at 87%. In contrast, March is much colder, with temperatures dipping to a minimum of -10°C (13°F) and averaging just 0°C (33°F), peaking at a mere 7°C (44°F). It sees less precipitation at 50 mm (2.0 in) over about 10 days, but a slightly higher humidity level of 90%. For a detailed look at March weather conditions, visit Hanko weather in March.
September and April present quite different weather patterns. In September, temperatures range from a minimum of 7°C (45°F) to a maximum of 20°C (68°F), with an average of 14°C (57°F), making it significantly warmer than April, where the temperatures vary from -2°C (29°F) to 9°C (49°F) and average around 3°C (38°F). Additionally, September experiences more rainfall, totaling 71 mm (2.8 in) over about 14 days, compared to just 28 mm (1.1 in) over 7 days in April. Despite similar humidity levels of 87%, the overall climate in September feels much milder and more inviting than the chill of April. For more details, you can visit Hanko weather in April.
In comparing the weather between September and May, September tends to be milder with average temperatures ranging from a chilly 7°C (45°F) to a comfortable 20°C (68°F), while May sees cooler temperatures, offering lows of just 1°C (35°F) and highs up to 18°C (64°F). September experiences more frequent rain, with precipitation occurring on 14 days and totaling 71 mm (2.8 in), compared to May's relatively drier conditions with only 36 mm (1.4 in) of rain over 7 days. Additionally, the humidity in September is notably higher at 87%, in contrast to May's 76%, making the early autumn month feel quite damp. For a closer look at May's weather specifics, you can check Hanko weather in May.
In comparing the weather in September and June, both months feature similar average temperatures, hovering around 14°C (57°F). However, September tends to be slightly cooler overall, with maximum temperatures reaching 20°C (68°F), compared to June's higher maximum of 22°C (73°F). Precipitation is notably higher in September, with 71 mm (2.8 in) spread across about 14 days, whereas June experiences only 37 mm (1.5 in) over just 6 days. Additionally, September has a higher humidity level at 87%, compared to June's 80%. For more detailed information, you can check Hanko weather in June.
When comparing the weather in September to that of July, notable differences emerge. September tends to be cooler, with minimum temperatures around 7°C (45°F) and an average of 14°C (57°F), while July experiences milder conditions, with minimums of 12°C (53°F) and an average temperature of 17°C (63°F). The maximum temperatures in July can reach up to 25°C (76°F), significantly higher than September's maximum of 20°C (68°F). Additionally, September sees more precipitation, with around 71 mm (2.8 in) falling over 14 days, compared to July's 57 mm (2.2 in) over just 8 days. Humidity is also slightly higher in September at 87%, compared to 80% in July. For more details on July weather, visit Hanko weather in July.
September experiences cooler temperatures compared to August, with September's minimum at 7°C (45°F) and maximum at 20°C (68°F), while August ranges from a minimum of 11°C (51°F) to a maximum of 23°C (73°F). Additionally, September is marked by slightly higher humidity at 87%, compared to August’s 83%. Both months see a significant amount of precipitation, but September has 71 mm (2.8 inches) over 14 days, while August has 94 mm (3.7 inches) over 13 days. For those interested in a more detailed overview, check out Hanko weather in August.
September typically showcases milder temperatures, with a minimum of 7°C (45°F) and an average of 14°C (57°F), reaching a maximum of 20°C (68°F). While it averages 71 mm (2.8 in) of precipitation over 14 days, the humidity remains relatively high at 87%. In contrast, October brings a noticeable chill, starting with minimum temperatures dropping to 1°C (35°F) and an average of 10°C (49°F), peaking at 16°C (61°F). The month is also wetter, with 123 mm (4.8 in) of precipitation over 19 days, and the humidity slightly increases to 90%. The transition between these two months highlights the shift from early autumn warmth to the crisp, damp days of late fall. For more detailed insights into October weather, you can refer to Hanko weather in October.
September and November exhibit notable differences in weather patterns. September generally enjoys milder temperatures, with averages around 14°C (57°F) and maximums reaching up to 20°C (68°F), while November sees a significant drop, with average temperatures around 6°C (43°F) and maximums peaking at 13°C (56°F). Precipitation is slightly higher in November at 82 mm (3.2 in), compared to September's 71 mm (2.8 in), but it occurs over more days, with 17 days in November versus 14 days in September. Humidity levels also increase from September's 87% to November's 91%, contributing to a more frigid atmosphere. For a more detailed look at Hanko's weather patterns in November, visit Hanko weather in November.
In September, the weather is relatively mild, with average temperatures ranging from a minimum of 7°C (45°F) to a maximum of 20°C (68°F), and average humidity around 87%. This month experiences approximately 71 mm (2.8 in) of precipitation spread over 14 days. In contrast, December brings much colder conditions, with temperatures plunging to a minimum of -9°C (17°F) and averaging only 2°C (36°F), peaking at a maximum of 8°C (46°F). December sees an increase in precipitation to 80 mm (3.1 in), occurring over 19 days, along with slightly higher humidity at 90%. For more detailed information, check out Hanko weather in December.
As September rolls into Hanko, the weather begins to shift noticeably from the warm summer months. With cooler temperatures and increased humidity, the month showcases a distinct transition towards autumn, making it a unique time to experience the changing scenery. Rainfall becomes more frequent, contributing to lush landscapes and a fresh atmosphere. The blend of mild warmth and increasing precipitation invites residents and visitors alike to embrace cozy days, which stand in contrast to the sun-soaked experiences of July and August. To learn more about what to expect in different seasons, explore Hanko Climate.