Last updated: August 21, 2025
September in Oulu, Finland presents a unique blend of early autumn charm and changing weather patterns. With a maximum temperature reaching 24°C (75°F) and an average of 10°C (49°F), the month offers a gentle transition from the warmth of summer to the crispness of fall. However, as temperatures dip to a chilly -4°C (24°F) at night, layers become essential for comfort. Rainfall is common, contributing 71 mm (2.8 in) over approximately 13 days, accompanied by a high humidity level of 90%. This combination of elements creates a distinct atmosphere, making September a fascinating time to experience the natural beauty and evolving landscapes of Oulu.
As summer gives way to autumn, September in Oulu, Finland marks a noticeable transition in temperatures. The month begins with a hint of warmth, showcasing maximum temperatures that can reach up to 24°C (75°F), perfect for enjoying the vibrant fall colors. However, the nights grow cooler, with minimum temperatures dipping to around -4°C (24°F), a stark reminder of the approaching chill of winter. The average temperature of 10°C (49°F) reflects this shift, indicating that while early September may still feel somewhat summery, the crispness of autumn soon prevails, inviting residents and visitors alike to embrace the change in the air. As the days shorten and the leaves begin to fall, September serves as a beautiful bridge between the warmth of summer and the biting cold of the months to follow.
In September, Oulu, Finland experiences a significant shift in its precipitation patterns as summer gives way to autumn. With 71 mm (2.8 in) of rainfall spread over 13 days, the month balances the lingering warmth with an uptick in wet weather compared to August's peak of 91 mm (3.6 in). Notably, September's precipitation is reflected in the changing landscape, where vibrant foliage begins to dominate the scenery. This month marks a transition from the rainy days of summer, yet it still sets the stage for the wetter months ahead, particularly October, which averages 81 mm (3.2 in) over 15 days. Overall, September serves as a reminder of nature's rhythm, heralding the approach of the colorful autumn season while also maintaining a steady level of moisture.
As the vibrant hues of September unfold in Oulu, Finland, humidity levels settle at a comfortable 90%, marking a noticeable increase from the summer months. This trend reflects the gradual transition into the autumn season, where the previously milder July and August experiences with 79% and 84% humidity give way to the heavier, moisture-laden air that typically accompanies fall. Following September, the humidity rises again in October and November, hitting 95%, suggesting a pattern of increasing dampness as winter approaches. Overall, September serves as a pivotal bridge between the warm, humid days of summer and the cool, crisp atmosphere of autumn, inviting residents to experience the beauty of nature’s seasonal shift.
As September unfolds in Oulu, Finland, residents experience a moderate UV Index of 3, signifying a notable shift after the peak summer months. This moderate exposure category suggests that while sun protection is still advisable, the risk of harm from unprotected sun exposure is lower compared to the high UV levels of June and July. With a burn time of 30 minutes, outdoor enthusiasts can enjoy the mild fall weather without excessive concern, provided they take sensible precautions. This transition toward autumn represents a gradual decrease in UV radiation, mirroring the trends seen throughout the year. For more detailed insights into the UV Index in Oulu, check out Oulu UV Index.
UV Risk Categories
As summer winds down, September in Oulu, Finland, showcases a notable transition in daylight, boasting around 280 hours of sunshine. This month marks a significant shift from the peak summer brightness, with June and July basking in over 500 hours of sun, to a more tempered luminosity as autumn approaches. The gradual decline in sunlight begins in August, yet September retains a charming glow, providing a beautiful backdrop for the changing foliage. This transition serves as a reminder of the vibrant seasons in Oulu, where the diminishing hours of daylight lead into the quieter months of autumn, reflecting a harmonious cycle of nature and light.
As summer fades into autumn, the likelihood of experiencing sunny weather in September in Oulu, Finland, drops to 27%. This marks a noticeable decline from the peak sunshine of July, which boasts a generous 56% chance. Following the vibrant summer months, the shift in weather patterns begins, with September's chances of sun closely resembling those seen in the spring months of April and May. While the lingering warmth prompts expectations for pleasant days, residents and visitors may find themselves contending with the increasing prevalence of cloud cover as they embrace the early whispers of fall.
As September unfolds in Oulu, Finland, daylight begins to wane, offering a striking transition from the long, sunlit days of summer. With approximately 12 hours of daylight, this month marks a notable decrease from August's 16 hours, hinting at the approach of autumn. The gradual reduction in daylight is a familiar rhythm in Oulu, where the sun shines brightly for nearly 21 hours in June, creating an inviting atmosphere for summer activities. The gradual descent from those lengthy days through the months reveals a natural ebb and flow, with each season showcasing its unique character. As the days shorten further into October, the essence of September serves as a bittersweet reminder of summer's fleeting warmth and the impending embrace of the long winter nights ahead.
In September, Oulu experiences a gentle average wind speed of 3.3 m/s (7 mph), mirroring the calm breezes of the previous month. This steady wind pattern continues a trend of relative consistency throughout the summer, with wind speeds maintaining a modest level from June to August. As the season transitions into autumn, September stands as a bridge between the lighter winds of summer and the invigorating gusts that characterize the coming months, as evident in the slight uptick anticipated in October, where speeds rise to 4.1 m/s (9 mph). Overall, September's winds enhance the city's charm, providing a refreshing breath of air as the landscape shifts towards fall.
Weather in Oulu varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Oulu, focusing on differences in temperature, rainfall, humidity, and UV levels.
September and January exhibit stark contrasts in weather. In September, temperatures range from a chilly -4°C (24°F) to a pleasant maximum of 24°C (75°F), with an average of 10°C (49°F). This month experiences relatively high humidity at 90% and receives about 71 mm (2.8 in) of precipitation over 13 days. In contrast, January plunges into frigid temperatures, with minima reaching -32°C (-25°F) and a maximum of only 5°C (41°F), resulting in a much colder average of -7°C (19°F). Additionally, January has lower precipitation at 40 mm (1.6 in) over 10 days and is characterized by 100% humidity. For more detailed information, check Oulu weather in January.
September and February present stark contrasts in weather conditions. In September, temperatures range from a chilly minimum of -4°C (24°F) to a comfortable maximum of 24°C (75°F), with an average of 10°C (49°F). The month sees about 71 mm (2.8 in) of precipitation spread over 13 days, accompanied by a relatively high humidity of 90%. In stark contrast, February experiences much colder temperatures, with a minimum of -25°C (-14°F) and an average of -8°C (17°F), peaking at just 5°C (42°F). Precipitation is less frequent, totaling 40 mm (1.6 in) over 9 days, and humidity rises to an impressive 98%. To learn more about the weather specifics in February, visit Oulu weather in February.
In September, temperatures in Oulu range from a chilly minimum of -4°C (24°F) to a warm maximum of 24°C (75°F), with an average temperature of 10°C (49°F). The month sees around 71 mm (2.8 in) of precipitation over 13 days, accompanied by a high humidity level of 90%. In contrast, March is significantly colder, with temperatures dropping to a minimum of -26°C (-15°F) and reaching a maximum of just 7°C (45°F), averaging -4°C (25°F). Precipitation is lighter, totaling 41 mm (1.6 in) over 11 days but comes with a slightly higher humidity of 95%. For more details on March weather specifically, you can visit Oulu weather in March.
When comparing the weather in September and April, we find significant differences in temperature and precipitation. September typically offers milder conditions, with average temperatures around 10°C (49°F) and highs reaching up to 24°C (75°F), while April tends to be much cooler, with average temperatures around 1°C (34°F) and maximums of only 14°C (57°F). In terms of precipitation, September experiences more rain, with 71 mm (2.8 in) over approximately 13 days, whereas April sees less rain, totaling 38 mm (1.5 in) over just 7 days. Humidity levels are relatively similar, with September at 90% and April slightly lower at 87%. For more specific details about April weather, visit Oulu weather in April.
In comparing the weather of September and May, September typically experiences milder temperatures, with an average of 10°C (49°F) and a maximum of 24°C (75°F), while May has slightly cooler conditions, averaging 7°C (45°F) and a high of 27°C (80°F). However, September can be more humid, with humidity levels around 90%, compared to May's 81%. Precipitation is more frequent in September, averaging 71 mm (2.8 in) over 13 days, whereas May sees less rain at 49 mm (1.9 in) across just 8 days. For more specific details on May weather, you can visit Oulu weather in May.
September and June present contrasting weather conditions. In September, temperatures range from a chilly minimum of -4°C (24°F) to a pleasant maximum of 24°C (75°F) with an average of 10°C (49°F). The month experiences significant precipitation, totaling 71 mm (2.8 in) over 13 days, and the humidity is notably high at 90%. In contrast, June boasts milder weather with a minimum temperature of 1°C (34°F), an average of 14°C (58°F), and a maximum of 29°C (85°F). With 60 mm (2.4 in) of rainfall spread across 9 days, June also experiences lower humidity levels at 77%. For a deeper look into June's climate specifics, you can check out Oulu weather in June.
In comparing the weather between September and July, it's clear that July is generally warmer, with average temperatures reaching 17°C (63°F) and maximums soaring up to 32°C (90°F), while September sees much cooler averages of 10°C (49°F) and a maximum of 24°C (75°F). However, September has a slightly higher frequency of precipitation, with rain occurring on 13 days and a total of 71 mm (2.8 in), compared to July's 73 mm (2.9 in) over 11 days. Humidity levels are also higher in September at 90%, compared to 79% in July, making the summer month feel more comfortable overall. For further details on July weather, you can check out Oulu weather in July.
In comparing the weather of September to August, we see a noticeable decline in temperatures, with September experiencing minimums of -4°C (24°F) and average highs of 24°C (75°F), compared to August's warmer minimum of 1°C (34°F) and average high of 31°C (88°F). While both months have significant rainfall, September has slightly less precipitation with 71 mm (2.8 in) over 13 days, compared to August's 91 mm (3.6 in) over 14 days. Additionally, September's humidity levels are higher at 90% compared to August's 84%, contributing to a cooler and more damp atmosphere. For a more detailed look at August's conditions, you can visit Oulu weather in August.
September and October display a noticeable shift in weather patterns. In September, temperatures range from a minimum of -4°C (24°F) to a maximum of 24°C (75°F), with an average of 10°C (49°F). The month experiences about 71 mm (2.8 in) of precipitation over 13 days, paired with a humidity level of 90%. In contrast, October brings a drop in temperatures, with a minimum of -12°C (10°F), an average of 4°C (40°F), and a maximum of 18°C (64°F). Precipitation increases slightly to 81 mm (3.2 in) spread over 15 days, and humidity rises to 95%. For a more detailed look at the weather in October, you can check Oulu weather in October.
September and November present stark contrasts in weather conditions. September enjoys a more moderate temperature range, with minimums around -4°C (24°F) and maximums reaching up to 24°C (75°F), while November plunges to much colder levels, featuring minimums of -18°C (0°F) and average temperatures around -1°C (31°F). Precipitation is relatively similar, with September receiving 71 mm (2.8 in) and November slightly less at 62 mm (2.4 in), both experiencing rainfall on approximately 13 days. Additionally, humidity levels climb from 90% in September to 95% in November, contributing to a distinctly chillier atmosphere. For more detailed information, check out Oulu weather in November.
In September, Oulu experiences milder weather with average temperatures around 10°C (49°F), ranging from a minimum of -4°C (24°F) to a maximum of 24°C (75°F). The month sees some rainfall, with a total of 71 mm (2.8 in) over 13 days, and a relatively high humidity level of 90%. In contrast, December brings much colder temperatures, with an average of -5°C (24°F), a minimum of -24°C (-12°F), and a maximum of just 4°C (40°F). While precipitation slightly decreases to 58 mm (2.3 in) over 14 days, the humidity rises to a peak of 99%, creating a much chillier and damp environment. For more details, you can explore Oulu weather in December.
As September unfolds in Oulu, the weather transitions into a cooler embrace, marking a noticeable change from the warmer summer months. Average temperatures dip to a refreshing 10°C (49°F), making outdoor activities more invigorating yet crisp. With 71 mm (2.8 in) of precipitation spread across about half the month, the skies often drape Oulu in a soft, rainy veil, which contributes to the lush autumn landscape. The increased humidity, hovering around 90%, adds a distinct chill to the air, contrasting sharply with the balmy summer days. As this month unfolds, it becomes clear that September serves as a beautiful and brisk prelude to the colder months ahead. For more insights on Oulu's climate variations, be sure to explore Oulu Climate.