Last updated: August 27, 2025
September in Slovenia offers a delightful blend of warm temperatures and refreshing autumnal air. With maximum temperatures reaching up to 32°C (90°F) and an average of 20°C (68°F), the month invites outdoor activities, while cooler nights dip to a pleasant 9°C (49°F). Visitors should prepared for approx. 164 mm (6.4 in) of rainfall spread over 10 days, ensuring the landscape remains lush and vibrant. The average humidity level of 64% adds to the comfortable feel, making September a truly enchanting time to experience Slovenia’s natural beauty.
As summer gives way to autumn, September in Slovenia presents a delightful transition in temperatures. With minimums around 9°C (49°F) and averages reaching 20°C (68°F), visitors can enjoy pleasantly warm days. The maximum temperature peaking at 32°C (90°F) hints at lingering summer warmth, making it an ideal time for outdoor activities and exploring the stunning landscapes. Compared to the sweltering heat of July and August, September offers a refreshing break, as the crispness in the air begins to signal fall’s imminent arrival. This blend of comfortable warmth and vibrant scenery creates a picturesque backdrop for travelers seeking both relaxation and adventure.
September marks a significant uptick in precipitation in Slovenia, with a notable 164 mm (6.4 in) of rainfall over 10 days. This surge positions September as one of the wettest months of the year, following the relatively dry summer months of July and August, which averaged around 65 mm and 70 mm respectively. While early autumn brings a refreshing change, the increased rainfall sets the stage for the transition into the wetter months ahead, particularly as October follows with a substantial 107 mm (4.2 in). This trend underscores Slovenia's dynamic weather patterns, where the shift from summer to autumn is often characterized by a marked increase in precipitation, preparing the landscape for the lushness that comes with the coming months.
As summer transitions into autumn, September in Slovenia witnesses a noticeable shift in humidity, averaging 64%. This marks an increase from the drier August, which boasted a significantly lower humidity level of 51%. While still relatively comfortable, September's humidity begins to inch upwards, hinting at the wetter months ahead. In fact, the trend for the rest of the year sees a steady rise, culminating in the more saturated conditions of October, which spikes back up to 83%. Thus, September serves as a pivotal point, bridging the dry warmth of summer and the damp chill that characterizes Slovenia’s later months.
In September, Slovenia experiences a noticeable transition in its UV Index, with a reading of 7, indicating a high exposure category. This marks a slight decrease from the peak summer months of July and August, where values reached 9 and 8, respectively. However, it's essential to remain vigilant, as the burn time extends to 25 minutes under direct sunlight. As the days grow shorter, the UV radiation begins to lessen, paving the way for a more moderate exposure in October. For anyone planning outdoor activities, it’s a good time to stay informed about the UV Index to ensure safe sun exposure. For more details, visit UV Index.
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As summer gently fades into autumn, September in Slovenia boasts a delightful 326 hours of sunshine, a mark of the lingering warmth that lingers from the height of summer. Following July's peak of 430 hours, the days gracefully shorten, yet they retain a generous glow, inviting visitors to embrace the beauty of the changing seasons. This transition is reflected in the decrease from August's 397 hours, hinting at the forthcoming cooler months. However, September remains vibrant and lively, showcasing stunning landscapes that shimmer in the golden light, making it a perfect time for exploration and adventure amidst the enchanting Slovene countryside.
September in Slovenia boasts a favorable 59% chance of sunny weather, making it one of the more promising months for sunshine. As summer transitions into autumn, the likelihood of clear skies remains relatively high, especially compared to the chillier months that follow. Notably, September's sun probability sits just behind the summer peak of August at 61%, indicating a slight but pleasant reduction in sunshine as the season changes. This trend reflects September's role as a bridge between summer's warmth and the cooler days of autumn, providing an optimal window for outdoor activities and exploration in the beautiful Slovenian landscape.
As summer gives way to autumn in Slovenia, September brings a gentle transition in daylight duration, offering around 12 hours of natural light each day. This marks a noticeable decrease from the sun-drenched days of July and August, which boast up to 15 hours of daylight. The gradual shift from the long days of summer highlights the progression toward shorter daylight hours, a trend that continues into October with only 10 hours remaining. Although September's daylight is less than the enchanting summer months, it still captures the beauty of early fall, where the vibrant landscapes start to transform in preparation for the quieter months ahead.
As September unfolds in Slovenia, the average wind speed gently recedes to 2.4 m/s (5 mph), marking it as one of the calmer months of the year. This mild breeze contrasts with the slightly brisk conditions found in preceding months, where wind speeds peaked at 3.2 m/s (7 mph) in May. The transition into autumn is palpable, as the winds become softer, paving the way for October's invigorating gusts that rise again to 3.6 m/s (8 mph). This subtle shift not only characterizes September's tranquil ambiance but also hints at the natural rhythm of the seasons, where the winds whisper of change before the invigorating energy of fall sets in.
Weather in varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in , focusing on differences in temperature, rainfall, humidity, and UV levels.
September and January present strikingly contrasting weather patterns. In September, temperatures range from a mild minimum of 9°C (49°F) to a warm maximum of 32°C (90°F), making it a much warmer month with an average of 20°C (68°F). In comparison, January is much colder, with temperatures dropping to a minimum of -7°C (20°F) and peaking at just 13°C (56°F), averaging around 5°C (41°F). Additionally, September experiences higher precipitation levels of 164 mm (6.4 in) over approximately 10 days, while January sees only 56 mm (2.2 in) over about 7 days. Humidity also differs significantly, with September at 64%, while January boasts a higher humidity of 88%. For more detailed insights into January's weather, check out weather in January.
September and February showcase a stark contrast in weather conditions. In September, temperatures range from a mild 9°C (49°F) at night to a warm 32°C (90°F) during the day, with an average of 20°C (68°F). While it experiences 164 mm (6.4 in) of precipitation over 10 days, the humidity is relatively moderate at 64%. In contrast, February brings much colder temperatures, with a minimum of -6°C (22°F) and a maximum of only 19°C (67°F), averaging 7°C (44°F). Although February sees slightly less rainfall at 118 mm (4.6 in) across the same number of days, the humidity is notably higher at 82%. For more details on February’s weather, check out weather in February.
September and March present quite contrasting weather conditions. In September, temperatures can range from a chilly 9°C (49°F) at night to a warm 32°C (90°F) during the day, with an average of 20°C (68°F), making it a generally mild month. However, it also experiences significant rainfall, totaling 164 mm (6.4 in) over about 10 days, accompanied by a humidity level of 64%. In stark contrast, March sees much cooler temperatures, with a minimum of -7°C (20°F) and an average of only 9°C (48°F), peaking at 21°C (70°F). Precipitation is considerably lower, at 71 mm (2.8 in) spread across 8 days, with humidity slightly higher at 73%. For a closer look at the weather in March, visit weather in March.
In comparing the weather between September and April, a noticeable contrast emerges. September boasts a more varied temperature range, with minimums around 9°C (49°F) and maximums reaching up to 32°C (90°F), leading to an average temperature of 20°C (68°F). In contrast, April is significantly cooler, with temperatures ranging from a minimum of 1°C (34°F) to a maximum of 25°C (77°F) and an average of only 13°C (55°F). While both months experience precipitation on about 10 days, September records a higher total of 164 mm (6.4 in), compared to April's 103 mm (4.0 in). Notably, April also has a higher humidity level at 73%, compared to September's 64%. For more detailed information, check out the weather in April.
When comparing the weather in September and May, several notable differences emerge. September typically boasts warmer temperatures, with an average of 20°C (68°F) and a maximum reaching 32°C (90°F), making it a pleasant transition from summer to fall. In contrast, May has slightly cooler average temperatures around 17°C (63°F) and maxing out at 27°C (81°F).
Precipitation levels are somewhat comparable, with September receiving 164 mm (6.4 in) over about 10 days, while May sees 142 mm (5.6 in) but over a longer span of 17 days, indicating a slightly wetter feel during the latter month. Additionally, humidity is higher in May at 70%, compared to 64% in September, contributing to a more humid environment as spring unfolds. For a detailed overview, you can check the weather in May.
In comparing the weather of September and June, we can see some notable differences. September typically experiences a wider temperature range, with minimums dropping to 9°C (49°F) and maximums reaching up to 32°C (90°F), while June has slightly warmer minimums at 11°C (53°F) and maximums peaking at 33°C (92°F). Precipitation in September is significantly higher, totaling 164 mm (6.4 in) over about 10 days, compared to June’s 87 mm (3.4 in) over just 8 days. Additionally, while humidity levels are relatively close, June tends to be a bit more humid at 69% compared to September's 64%. For a deeper look into June's specifics, you can check out this link: weather in June.
September weather in Koper shows marked variability, with temperatures ranging from a cool 9°C (49°F) at night to a warm 32°C (90°F) during the day, averaging around 20°C (68°F). In contrast, July typically experiences milder nights with temperatures starting at 16°C (61°F) and peaking at 33°C (91°F), averaging about 24°C (75°F). Additionally, September brings higher precipitation levels, with 164 mm (6.4 in) over around 10 days, compared to the much drier July, which sees just 65 mm (2.6 in) spread across 8 days. Humidity remains relatively similar in both months, hovering around 63-64%. For more details, you can check the weather in July.
In September, the weather experiences a notable shift from August, with average temperatures dropping from 25°C (77°F) to 20°C (68°F). The maximum temperature in September reaches 32°C (90°F), similar to August's peak of 34°C (94°F), but with significantly cooler minimum temperatures starting at 9°C (49°F) compared to August's 15°C (59°F). Additionally, September is wetter, with 164 mm (6.4 in) of precipitation over 10 days, surpassing August's 70 mm (2.7 in) over just 7 days. Humidity levels also increase in September to 64%, compared to 51% in August, contributing to a more humid atmosphere as the month progresses. For a detailed look at the weather trends, visit weather in August.
September typically presents warmer temperatures with an average of 20°C (68°F) and highs reaching up to 32°C (90°F), while October sees a noticeable drop, with average temperatures around 15°C (59°F) and maximums peaking at 23°C (74°F). Additionally, September experiences more sunshine and less humidity at 64%, in contrast to October's increased humidity levels of 83% and cooler minimum temperatures of 6°C (44°F). Precipitation is also lower in October with 107 mm (4.2 in) compared to September's 164 mm (6.4 in), although both months see rainfall on about 10 days. For more details, check the weather in October.
September and November exhibit contrasting weather patterns. In September, temperatures range from a minimum of 9°C (49°F) to a warm average of 20°C (68°F), peaking at a high of 32°C (90°F). The month experiences about 164 mm (6.4 in) of precipitation over approximately 10 days, with a humidity level of 64%. In contrast, November sees a significant drop in temperatures, with a minimum of 1°C (34°F) and an average of 11°C (52°F), reaching a maximum of 20°C (68°F). The rainfall increases slightly to 176 mm (6.9 in) spread over about 12 days, accompanied by a much higher humidity of 89%. For more details, check out the weather in November.
September and December showcase vastly different weather patterns. In September, temperatures range from a comfortable 9°C (49°F) at night to a warm 32°C (90°F) during the day, with an average of 20°C (68°F). The month sees 164 mm (6.4 in) of precipitation over about 10 days, with humidity levels around 64%. In contrast, December brings much cooler conditions, with temperatures dropping to a minimum of -1°C (30°F) and reaching a maximum of 15°C (60°F), averaging only 7°C (44°F). This month has a slight reduction in precipitation at 150 mm (5.9 in) but over a longer duration of approximately 12 days, and the humidity rises significantly to 88%. For more specifics on December's climate, check this link: weather in December.
As summer fades, September brings a refreshing change in Koper Capodistria's weather, offering a delightful blend of warmth and coolness. With temperatures averaging around 20°C, this month stands out with milder conditions compared to the scorching highs of July and August. Although it retains some heat, the days are interspersed with increased rainfall, totaling about 164 mm over ten days, which adds a touch of freshness to the air. The humidity hovers at a comfortable 64%, making it a perfect time for outdoor activities without the oppressive heat. For more insights into how September compares to other months, check out our detailed Climate page.