September Weather in , Slovenia

Last updated: August 27, 2025

In September, Slovenia experiences a delightful transition as summer begins to give way to autumn. Temperatures range from a maximum of 33°C (92°F) to a refreshing minimum of 3°C (38°F), averaging around 17°C (63°F), providing a perfect backdrop for outdoor activities. Despite a total precipitation of 111 mm (4.4 in) spread over 10 days, the weather remains inviting, with an average humidity of 65%. This makes September an ideal time to explore Slovenia’s stunning landscapes, vibrant cultures, and crisp, invigorating air.

September Temperature in

As summer transitions into autumn, September in Slovenia offers a delightful shift in temperatures. With minimums around 3°C (38°F) and averages peaking at 17°C (63°F), the month still retains some warmth, inviting outdoor activities and scenic explorations. The highs can reach a pleasant 33°C (92°F), reminiscent of the lingering summer days. This gradual cooling is a refreshing change from the earlier months, paving the way for the crispness of fall, while still providing ample opportunities to enjoy Slovenia's stunning landscapes bathed in early autumn hues. The comfortable temperatures starkly contrast the winter chill awaiting in the coming months, making September a perfect time to experience the beauty of this enchanting country.

September Weather in : Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in , showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In , September typically has an average temperature of {2}°C ({3}°F), with highs reaching up to {4}°C ({5}°F) and lows dropping to around {6}°C ({7}°F).
JanFebMarAprMayJunJulAugSepOctNovDec343944536170727263544537
Data source: Temperature data for generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in

In September, Slovenia experiences a significant spike in precipitation, with 111 mm (4.4 in) of rainfall recorded over 10 days. This marks one of the wettest months of the year, closely following the abundant rains of May, which saw a notable peak. As summer transitions to autumn, the moisture levels rise, indicating a shift in weather patterns. This trend highlights a continued increase in precipitation as the year progresses, contrasting distinctly with the drier winter months observed earlier, such as January and February. The lush landscapes that result from this late-summer rainfall create a captivating backdrop, as Slovenia's natural beauty flourishes under the nourishing embrace of September showers.

September Precipitation Trends in

The chart displays monthly precipitation patterns in , with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In , September typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec29514354123838780111647867
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in

As summer fades into autumn, September in Slovenia experiences a noticeable shift in humidity, averaging around 65%. This marks a slight increase from the drier summer months, where humidity dipped to 60% in August. The trend throughout the year showcases a gradual decline in humidity from the damp chill of winter, peaking at an impressive 90% in January, before reaching its annual low in July. However, as the season transitions, humidity levels begin to rise once again, hinting at the approaching wetness of fall, which can see percentages soaring back up to 84% by October. This dynamic shift underlines the typical Slovene climate, where the crispness of autumn brings a refreshing yet slightly more humid air.

September Average Humidity in

This chart illustrates the average monthly humidity levels in , with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in is approximately {2}%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec90%84%78%73%71%73%70%60%65%84%89%89%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in

As September rolls into Slovenia, the UV Index settles at 6, indicating a high exposure category with a burn time of 25 minutes. This marks a noticeable shift from the intense summer months of June and July, where the index peaked at 9, demanding only a brief 15 minutes of sun exposure. In contrast, as summer fades, the UV levels decrease while still maintaining a significant intensity, reminding sun-seekers to be vigilant. The mild temperatures and reduced UV risk provide a perfect opportunity for outdoor activities—just remember to apply sunscreen to protect your skin! For more detailed insights, check out the UV Index in your area.

Maximum UV Index Levels in for September

The chart shows the monthly maximum UV Index (UVI) for in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In September, the maximum UV index in typically reaches {2}, which falls under the {3} exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec235689986422
Data source: September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

September Sunshine in

As summer yields to autumn, September in Slovenia offers a beautiful blend of golden sunshine, with 325 hours illuminating the month. This reflects a gentle decline from the peak of July's 425 hours, signaling the shift from the vibrant energy of summer to the cooler embrace of fall. The sunshine during September still benefits from the lingering warmth of summer, providing a pleasant backdrop for outdoor adventures. Interestingly, as the month progresses into October, a noticeable drop to 285 hours emerges, foreshadowing the shorter days ahead. This trend illustrates a seasonal transition, where sunshine not only lights up the picturesque landscapes but also marks the approach of Slovenia's quieter autumn months.

Monthly Sunshine Duration in : September Highlighted

The September sunshine duration represents the total number of hours experiences direct sunlight during the month of September, excluding cloudy or obstructed periods. This chart compares the sunshine duration of September with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec162h224h298h331h367h404h425h390h325h285h201h198h
Data source: September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in During September

As September rolls in, Slovenia enjoys a 52% chance of sunny weather, making it one of the more favorable months for sunshine compared to the earlier part of the year. After a summer marked by varied sunshine—peaking at 56% in June and dipping to 46% in August—September offers a pleasant balance, sitting comfortably above the annual average. While the promise of sunny days diminishes toward autumn, with October seeing a drop to 43%, September stands out as a sweet spot for light, inviting visitors to bask in the early fall warmth and the stunning landscapes that Slovenia has to offer.

Percentage of Sunny Days in September in

The chart illustrates the percentage of sunny days in throughout the year, with September highlighted. It highlights the variation in sunshine across each month and provides an overview of the typical frequency of sunny days, offering insights into how often experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec27%50%55%40%38%56%48%46%52%43%26%30%
Data source: September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in in September

As summer gracefully transitions into autumn, September in Slovenia offers a delightful 12 hours of daylight, marking a gradual decline from the sun-drenched days of July and August, which boast 15 hours of light. This month serves as a bridge between the vibrant long days of summer and the shorter, cozier days of fall. Following the peak daylight duration in June, visitors can observe that as nature begins to prepare for the cooler months ahead, daylight starts to wane. The steady decrease in daylight hours that commenced in late summer highlights the seasonal rhythm, inviting both locals and travelers to savor the perfect balance of warmth and evening sunsets before the days shrink further into October's 10 hours of light.

Average Daylight Hours in for September

The chart illustrates the variation in daylight duration in throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 1m10h 19m11h 56m13h 35m15h 1m15h 44m15h 21m14h 5m12h 30m10h 51m9h 23m8h 37m
Data source: daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in

As we transition into September in Slovenia, the landscape undergoes subtle yet captivating changes, mirrored by a slight uptick in wind speeds. Averaging 1.9 m/s (4 mph), September winds breathe a gentle freshness into the air, serving as a precursor to the more dynamic breezes of autumn. This mild increase from August, which saw the year's lowest winds at 1.8 m/s (4 mph), hints at nature's shift, as the days begin to shorten and the temperatures cool. Observing the trends throughout the year, September’s winds are a gentle reminder of summer's retreat while softly inviting the briskness of fall, encapsulating the beauty of transition that defines this enchanting season in Slovenia.

Average September Wind Speed in

The chart displays monthly wind speed patterns in , with values for each month shown alongside September's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how September's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec2.62.72.62.92.82.22.51.81.9 m/s2.62.02.2
Data source: September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Compares to Other Months

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 showcase contrasting weather patterns. In September, temperatures can range from a cool 3°C (38°F) at the minimum to a warm 33°C (92°F) at the maximum, with an average of 17°C (63°F). This month experiences about 111 mm (4.4 in) of precipitation over approximately 10 days and has a humidity level of 65%. In stark contrast, January brings frigid temperatures, with lows plunging to -15°C (6°F) and averages sitting at just 1°C (34°F), peaking at 14°C (58°F). The precipitation is significantly lower at 29 mm (1.2 in) spread over 6 days, and the humidity is higher at 90%. For a more detailed look at January conditions, visit weather in January.

September typically brings a more moderate climate with average temperatures ranging from a minimum of 3°C (38°F) to a maximum of 33°C (92°F). With an average of 17°C (63°F), the weather is generally warm and pleasant, although it can experience significant rainfall of about 111 mm (4.4 in) over approximately 10 days, and a humidity level of around 65%.

In contrast, February experiences much colder temperatures, with an average low of -12°C (11°F) and a maximum of 20°C (68°F), resulting in a chilly average of 4°C (40°F). Precipitation is significantly lower than in September, at 51 mm (2.0 in) across about 7 days, yet humidity is notably higher at 84%. For more details on the climatic conditions, you can check the weather in February.

September and March exhibit strikingly different weather patterns. In September, temperatures range from a chilly 3°C (38°F) at night to a warm 33°C (92°F) during the day, with an average of 17°C (63°F). This month also sees significant precipitation, totaling 111 mm (4.4 in) over about 10 days, with humidity hovering around 65%. In contrast, March experiences much colder conditions, with temperatures dipping as low as -18°C (-1°F) and peaking at 23°C (73°F), averaging at 7°C (45°F). Precipitation is lower in March, at 43 mm (1.7 in) over roughly 8 days, but the humidity is notably higher at 78%. For more details on the weather in March, you can refer to weather in March.

September and April showcase contrasting weather patterns, reflecting the transition from summer to autumn and the end of winter to spring, respectively. In September, temperatures range from a cooler 3°C (38°F) at night to a warm 33°C (92°F) during the day, with an average of 17°C (63°F). In contrast, April experiences colder minimum temperatures, dipping to -5°C (23°F), while the maximum can reach 28°C (83°F) and averages around 12°C (53°F). Additionally, September sees higher precipitation levels of 111 mm (4.4 in) over ten days, compared to April’s 54 mm (2.1 in) over the same number of days. Interestingly, April has a higher humidity level at 73%, while September is at 65%. For more detailed insights, you can check the weather in April.

When comparing the weather in September to that of May, we can see distinct differences in temperature and precipitation patterns. September typically experiences a broader temperature range, with minimums reaching 3°C (38°F) and maximums soaring to 33°C (92°F), whereas May has slightly cooler minimums at 1°C (35°F) and maximums peaking at 32°C (89°F). Precipitation is another factor to consider; September brings 111 mm (4.4 in) over about 10 days, while May sees a bit more rain, accumulating 123 mm (4.8 in) across 17 days. Moreover, May tends to be slightly more humid, with humidity levels at 71%, compared to September's 65%. To explore more about the weather conditions specific to May, you can visit weather in May.

In comparing the weather of September and June, September tends to feature a more significant temperature range, with minimums dropping to 3°C (38°F) and maximums reaching up to 33°C (92°F). The average temperature for September is around 17°C (63°F), while June boasts a milder minimum of 8°C (46°F) and a higher maximum of 36°C (96°F), resulting in an average temperature of 21°C (71°F). Additionally, September experiences higher precipitation levels at 111 mm (4.4 in) over 10 days, compared to June's 83 mm (3.3 in) over 12 days. Humidity is also slightly lower in September at 65%, versus June's 73%. For more detailed information, you can check the weather in June.

In comparing the weather of September and July, September showcases a wider temperature range, with minimums dipping to 3°C (38°F) and maximums soaring up to 33°C (92°F), while July maintains milder temperatures from 11°C (51°F) to 36°C (97°F). The average temperature in September is slightly cooler at 17°C (63°F) compared to July's warmer average of 22°C (72°F). Precipitation-wise, September experiences more rainfall at 111 mm (4.4 in) over about 10 days, whereas July has a total of 87 mm (3.4 in) spread across 11 days. Additionally, humidity levels in July are a bit higher at 70%, compared to September's 65%. For more details, see the weather in July.

In September, the weather becomes noticeably cooler compared to August, with minimum temperatures dropping to 3°C (38°F) and an average of 17°C (63°F), significantly lower than the average of 22°C (73°F) in August. Additionally, September sees higher maximum temperatures of up to 33°C (92°F), whereas August can reach as high as 38°C (100°F). Precipitation also increases in September, totaling 111 mm (4.4 in) over 10 days, compared to 80 mm (3.1 in) over 9 days in August. Humidity is a bit higher in September at 65%, compared to 60% in August. For more details, you can check the weather in August.

In September, the weather is warmer with temperatures ranging from a chilly 3°C (38°F) at night to a scorching 33°C (92°F) during the day, averaging 17°C (63°F). This month experiences significant rainfall, totaling 111 mm (4.4 in) over about 10 days, coupled with a moderate humidity of 65%. In contrast, October sees a notable drop in temperatures, with minimums dipping to 0°C (32°F) and daily highs peaking at 26°C (79°F), leading to an average temperature of 12°C (54°F). Rainfall also decreases to 64 mm (2.5 in) across approximately 8 days, but humidity rises to 84%, creating a much more damp atmosphere. For more detailed information, you can explore the weather in October.

In September, the weather features a broad temperature range, with minimums around 3°C (38°F) and maximums climbing up to 33°C (92°F), averaging 17°C (63°F). This month typically sees about 111 mm (4.4 in) of rainfall over 10 days, accompanied by a moderate humidity level of 65%. In contrast, November brings significantly cooler conditions with minimum temperatures dropping to -5°C (22°F) and maximums peaking at 20°C (69°F), leading to an average of just 7°C (45°F). Although precipitation decreases to 78 mm (3.1 in) over 9 days, the humidity rises to 89%, making the air feel considerably cooler and damp. For more details on November weather, you can check this link: weather in November.

September and December present markedly different weather conditions. In September, temperatures typically range from a minimum of 3°C (38°F) to a maximum of 33°C (92°F), with an average of 17°C (63°F). The month experiences considerable rainfall, totaling 111 mm (4.4 in) across about 10 days, along with a humidity level of 65%. In contrast, December features cooler temperatures, with a minimum of -6°C (22°F) and a maximum of 18°C (64°F), averaging just 3°C (37°F). Precipitation decreases to 67 mm (2.7 in) over 8 days, but the humidity significantly rises to 89%. For a more detailed look at December's weather, visit weather in December.

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Conclusion: What to Expect From September Weather in

As summer gently gives way to autumn, September ushers in a unique shift in weather compared to the warmer months. With an average temperature of 17°C, the air feels fresher, yet the remnants of warmth linger, peaking at a maximum of 33°C and sometimes dipping as low as 3°C. This month stands out not just for its milder temperatures, but also for its notable rainfall, totaling 111 mm over about ten days, contributing to the lush landscape. The humidity level hovers at 65%, adding a touch of moisture to the crisp air. For a deeper understanding of how these patterns shape the environment, explore the comprehensive details in our section on Climate.