September Weather in Ljubljana, Slovenia

Last updated: August 27, 2025

September in Ljubljana, Slovenia showcases a delightful transition into autumn, with maximum temperatures reaching a warm 29°C (85°F) while the average settles at a comfortable 16°C (61°F). Crisp mornings can surprise with lows dipping to 2°C (35°F). Expect a generous 159 mm (6.3 in) of rainfall spread across 12 days, adding a refreshing touch to the lush greenery. With humidity around 64%, visitors can enjoy the city's stunning architecture and vibrant culture amidst pleasantly mild conditions.

September Temperature in Ljubljana

As September arrives in Ljubljana, Slovenia, the city basks in the warmth of late summer, with temperatures gradually shifting from the heights of August. The month showcases a pleasant average temperature of 16°C (61°F), making it an inviting time for outdoor activities. Daily highs can reach up to 29°C (85°F), while the nights cool down to a comfortable 2°C (35°F). This transition signals the start of autumn, as the vibrant summer days begin to fade, yet there's still ample opportunity to enjoy the lingering warmth before cooler months set in. Overall, September in Ljubljana is marked by a refreshing balance of warmth and crispness, setting the stage for the enchanting colors of fall.

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

The chart illustrates September temperature patterns in Ljubljana, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Ljubljana, 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).
JanFebMarAprMayJunJulAugSepOctNovDec333843505867697060524336
Data source: Temperature data for Ljubljana 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 Ljubljana

In September, Ljubljana experiences a significant uptick in precipitation, with 159 mm (6.3 in) of rainfall over the month, making it one of the wettest periods of the year. This is particularly notable as it marks a peak in precipitation, following the relatively drier summer months. With 12 rainy days, September averages about half the days drenched, setting the stage for the transition into autumn. This trend indicates that as summer wanes, the city prepares for its lush, verdant foliage, fueled by the increased moisture. It's a vivid reminder of nature's cyclical patterns, where the lushness of spring and summer gives way to the richer, darker tones of fall, all while the rain nurtures the landscape in a vibrant display.

September Precipitation Trends in Ljubljana

The chart displays monthly precipitation patterns in Ljubljana, 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 Ljubljana, September typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec51897194166849810016098131121
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Ljubljana

As summer transitions into autumn, September in Ljubljana experiences a noticeable shift in humidity levels. Following the warm and relatively dry months of July and August, where humidity dipped to a refreshing 63% and a low of 51% respectively, September sees a modest resurgence with humidity rising to 64%. This gradual increase hints at the approach of cooler months, setting the stage for the higher humidity typical of late autumn, with October peaking once again at 83%. Thus, September serves as a bridge, where lingering warmth is accompanied by a slight dampness, creating a perfect prelude to the atmospheric changes ahead.

September Average Humidity in Ljubljana

This chart illustrates the average monthly humidity levels in Ljubljana, 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 Ljubljana is approximately {2}%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%82%73%73%70%69%63%51%64%83%89%88%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Ljubljana

As September rolls into Ljubljana, Slovenia, the UV Index reflects a gradual transition from summer's intense rays towards the softer autumnal sunlight. With a UV Index of 7, categorized as high, residents and visitors can expect a burn time of 25 minutes—a decrease from the peak summer months. This shift signifies that while it's still essential to protect your skin, the urgency to seek shade isn't as critical as in July and August, where the index hit a notable 9. September offers an inviting balance, perfect for outdoor activities while reminding us to remain vigilant against UV exposure. For more details on daily UV levels, check out Ljubljana UV Index.

Maximum UV Index Levels in Ljubljana for September

The chart shows the monthly maximum UV Index (UVI) for Ljubljana 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 Ljubljana typically reaches {2}, which falls under the {3} exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec235689987532
Data source: Ljubljana 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 Ljubljana

As summer fades into autumn, September in Ljubljana embraces a delightful blend of warmth and light with 318 hours of sunshine. This month, while offering a softer glow compared to the sun-drenched days of July, still holds plenty of bright moments, attracting both locals and visitors to enjoy the city's charming outdoor cafés and picturesque landscapes. Comparatively, September's sunshine lingers comfortably above the more subdued tones of October and the drastically lower hours in the colder months that follow, setting the stage for a serene transition into fall. With the sun still shining brightly, September stands as a beautiful reminder of the lingering summer days while hinting at the cozy comforts of the approaching season.

Monthly Sunshine Duration in Ljubljana: September Highlighted

The September sunshine duration represents the total number of hours Ljubljana 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.
JanFebMarAprMayJunJulAugSepOctNovDec178h220h310h336h361h408h427h393h318h286h212h209h
Data source: Ljubljana September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Ljubljana During September

As September arrives in Ljubljana, Slovenia, the chance of sunny weather significantly brightens up the horizon, boasting a promising 51% likelihood of sunshine. This marks a slight increase compared to the preceding summer months, such as July (46%) and August (44%), indicating that the early autumn days often offer a delightful balance of warmth and pleasant skies. Furthermore, September stands out as it approaches the more unpredictable months ahead, illustrating a trend where the chances of sun gradually decline as the year progresses. With the vivid colors of fall beginning to emerge, September in Ljubljana beckons visitors to relish both the sunshine and the stunning scenery.

Percentage of Sunny Days in September in Ljubljana

The chart illustrates the percentage of sunny days in Ljubljana 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 Ljubljana experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec23%37%58%37%33%53%46%44%51%32%24%29%
Data source: Ljubljana September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Ljubljana in September

As summer transitions to autumn in Ljubljana, Slovenia, September brings a gentle decline in daylight, offering approximately 12 hours of sun. This marks a noticeable shift from the height of summer, where daylight peaked at 15 hours in June and July. The gradual reduction in daylight hours is reflective of the changing seasons, as the city bids farewell to the warmth of summer and welcomes the crisp air of fall. With September's luminous days, residents can still enjoy the balanced beauty of early autumn, as the evenings gradually draw in, paving the way for the shorter days of October and November ahead.

Average Daylight Hours in Ljubljana for September

The chart illustrates the variation in daylight duration in Ljubljana throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 5m10h 21m11h 56m13h 33m14h 57m15h 40m15h 17m14h 3m12h 29m10h 52m9h 26m8h 42m
Data source: Ljubljana daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Ljubljana

As the vibrant month of September arrives in Ljubljana, the city's atmosphere is gently stirred by an average wind speed of 1.8 m/s (4 mph), marking a slight increase from the summer's calm breezes. This refreshing air, while still mild, signals the transition towards autumn, reflecting a subtle uptick in wind activity compared to the languid July and August months. The consistency of the wind speeds in the warmer months—hovering around 1.6 to 1.8 m/s—suggests a stable climate, providing a pleasant backdrop for outdoor activities. As September unfolds, residents and visitors alike can relish in the serene yet invigorating winds, perfect for leisurely strolls through the enchanting streets of Slovenia's capital.

Average September Wind Speed in Ljubljana

The chart displays monthly wind speed patterns in Ljubljana, 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.
JanFebMarAprMayJunJulAugSepOctNovDec2.02.52.02.22.11.71.81.61.8 m/s2.21.91.6
Data source: Ljubljana September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Ljubljana Compares to Other Months

Weather in Ljubljana varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Ljubljana, focusing on differences in temperature, rainfall, humidity, and UV levels.

September's weather is characterized by a wider temperature range, with minimums around 2°C (35°F) and maximums reaching 29°C (85°F), creating a pleasant average of 16°C (61°F). However, the month is also quite rainy, receiving 159 mm (6.3 in) of precipitation over 12 days, while humidity hovers at 64%. In contrast, January experiences much colder temperatures, with minimums plummeting to -12°C (11°F) and an average temperature of just 1°C (34°F). The winter month sees less rainfall, recording only 51 mm (2.0 in) over 7 days, though it has a higher humidity level of 88%. For more detailed information about January weather, you can visit Ljubljana weather in January.

In September, temperatures in Ljubljana range from a brisk minimum of 2°C (35°F) to a warm maximum of 29°C (85°F), with an average of 16°C (61°F). The month sees considerable rainfall, averaging 159 mm (6.3 in) over about 12 days, and humidity levels hover around 64%. Conversely, February presents a stark contrast with much colder temperatures, dipping to a minimum of -11°C (13°F) and peaking at 19°C (67°F), averaging only 4°C (39°F). Although February has less precipitation at 88 mm (3.5 in) over 9 days, the humidity is notably higher at 82%. For more detailed information, you can explore Ljubljana weather in February.

In comparing September and March weather, September showcases a broader temperature range with a minimum of 2°C (35°F) and a pleasant average of 16°C (61°F), reaching up to a warm 29°C (85°F). Precipitation is relatively high at 159 mm (6.3 in) over 12 days, accompanied by a humidity level of 64%. Conversely, March experiences colder temperatures, with a minimum of -14°C (8°F) and an average of 6°C (43°F), peaking at 22°C (71°F). Although March has lower total precipitation of 71 mm (2.8 in) spread over 10 days, it also features slightly higher humidity at 73%. For more detailed insights about weather conditions, check out Ljubljana weather in March.

When comparing the weather between September and April, notable differences emerge in both temperature and precipitation. September typically enjoys milder weather with average temperatures ranging from a minimum of 2°C (35°F) to a maximum of 29°C (85°F), resulting in a comfortable average of 16°C (61°F). In contrast, April experiences colder conditions, with temperatures ranging from a minimum of -11°C (13°F) to a peak of 26°C (79°F) and an average of only 10°C (51°F).

Precipitation levels also vary, as September sees 159 mm (6.3 in) over 12 days, while April has a lower total of 94 mm (3.7 in) across the same number of days. Additionally, humidity is generally higher in April at 73%, compared to 64% in September. For more details on April weather in Ljubljana, visit Ljubljana weather in April.

September and May offer distinct weather characteristics, though both months experience mild temperatures. In September, the minimum temperature hovers around 2°C (35°F), with an average of 16°C (61°F) and a maximum reaching 29°C (85°F). This month typically sees about 159 mm (6.3 in) of precipitation over 12 days, with humidity averaging 64%. In contrast, May features slightly cooler temperatures, with a minimum of 1°C (34°F), an average of 14°C (58°F), and a maximum of 28°C (82°F). While precipitation is slightly higher at 166 mm (6.5 in), it spans over more days, totaling 19 days, contributing to a higher humidity level of 70%. For those curious about what to expect during May, further details can be found at Ljubljana weather in May.

September weather tends to be cooler compared to June, with temperatures ranging from a minimum of 2°C (35°F) to a maximum of 29°C (85°F), averaging around 16°C (61°F). In contrast, June enjoys warmer temperatures, with a range from a minimum of 6°C (43°F) to a maximum of 34°C (94°F), averaging 20°C (68°F). While both months experience precipitation over 12 days, September sees more rainfall at 159 mm (6.3 in) compared to June's 84 mm (3.3 in). Additionally, humidity levels in June are slightly higher at 69%, compared to September's 64%. For more details, check out Ljubljana weather in June.

September generally experiences cooler temperatures compared to July, with average lows of 2°C (35°F) rising to a maximum of 29°C (85°F), while July enjoys milder nights and warmer days, with temperatures ranging from a minimum of 10°C (51°F) to a maximum of 34°C (93°F). Both months experience significant precipitation; however, September is wetter with 159 mm (6.3 in) over 12 days, compared to July's 98 mm (3.9 in) over 13 days. Humidity levels remain similar, around 64% in September and 63% in July. For a more detailed look at July's climate specifics, check out Ljubljana weather in July.

In September, the weather features a broader temperature range with minimums dropping to 2°C (35°F) and maximums reaching up to 29°C (85°F), compared to August, which has milder minimums at 8°C (47°F) and higher maximums of 35°C (96°F). While September experiences more frequent rainfall, totaling 159 mm (6.3 in) over 12 days, August sees less precipitation at 100 mm (3.9 in) over the same number of days. Additionally, humidity rises significantly in September to 64%, compared to the more comfortable 51% experienced in August. For those interested in detailed weather patterns, more information can be found at Ljubljana weather in August.

September and October exhibit notable differences in weather patterns. In September, temperatures range from a minimum of 2°C (35°F) to a maximum of 29°C (85°F), with an average of 16°C (61°F), reflecting the warmth of late summer. The month also sees significant precipitation of 159 mm (6.3 in) over 12 days, with a humidity level of 64%. In contrast, October experiences cooler temperatures, ranging from a minimum of 0°C (31°F) to a maximum of 24°C (76°F), averaging 11°C (52°F). Additionally, precipitation declines to 98 mm (3.9 in) over 9 days, alongside an increase in humidity to 83%. For more detailed insights, you can check Ljubljana weather in October.

September weather is characterized by milder temperatures, with averages around 16°C (61°F) and a maximum of 29°C (85°F), creating a warm and pleasant atmosphere. In contrast, November brings cooler temperatures, with an average of 6°C (44°F) and nighttime lows dipping to -6°C (22°F), indicating the onset of winter. Despite slightly less precipitation in November at 131 mm (5.2 in) compared to September's 159 mm (6.3 in), the increased humidity of 89% in November adds to the brisk chill in the air. For more detailed information, visit Ljubljana weather in November.

September and December present stark contrasts in weather. In September, temperatures range from a cool 2°C (35°F) at night to a warm 29°C (85°F) during the day, with an average of 16°C (61°F). The month sees a fair amount of precipitation with 159 mm (6.3 in) over about 12 days, and humidity levels at a comfortable 64%. In contrast, December brings much colder conditions, with temperatures dropping to a minimum of -15°C (6°F) and only reaching a maximum of 14°C (58°F), resulting in an average of just 2°C (36°F). Although December has less precipitation at 121 mm (4.8 in) over 10 days, the humidity rises to a notable 88%. For more detailed insights on December weather, you can visit Ljubljana weather in December.

Compare Ljubljana's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Ljubljana

As September arrives in Ljubljana, the city begins to transition from the warmth of summer into the crisp embrace of autumn. Temperatures gradually cool down, with pleasant days that can still reach a maximum of 29°C (85°F), while the nights start to hint at the chill to come. This month sees a notable increase in precipitation, with September experiencing more rainy days compared to the dry summer months, leading to an average of 159 mm over approximately 12 days. The humidity remains comfortable at around 64%, making it a lovely time to explore the city's stunning scenery. For a deeper understanding of how Ljubljana's weather shifts throughout the year, visit Ljubljana Climate.