September Weather in Idrija, Slovenia

Last updated: August 27, 2025

September in Idrija, Slovenia presents a captivating transition into autumn, characterized by maximum temperatures reaching up to 29°C (85°F) and a comfortable average of 16°C (60°F). With minimum temperatures dropping as low as 2°C (36°F), this month showcases a delightful range in weather. However, be prepared for some rain, as 194 mm (7.6 in) of precipitation falls over approximately 13 days, driving an average humidity level of 64%. Whether you're exploring the charming streets or enjoying the natural beauty, Idrija's September weather offers a unique experience that embodies the allure of early fall.

September Temperature in Idrija

As September arrives in Idrija, Slovenia, the climate begins to transition from the warmth of summer to the cool embrace of autumn. With daily temperatures ranging from a pleasant 2°C (36°F) to a warm 29°C (85°F), this month presents delightful days accentuated by mild evenings. The average temperature hovers around 16°C (60°F), making it an ideal time for outdoor exploration as the vibrant colors of fall start to emerge. Compared to the sweltering heat of July and August, which can peak around 34°C (93°F), September offers a refreshing change, reminding locals and visitors alike of the beauty of seasonal shifts in this picturesque Slovenian town. With each passing day, the crispness in the air hints at the approaching autumn, inviting everyone to enjoy the enchanting landscapes that Idrija has to offer.

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

The chart illustrates September temperature patterns in Idrija, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Idrija, 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).
JanFebMarAprMayJunJulAugSepOctNovDec343842505767696960524336
Data source: Temperature data for Idrija 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 Idrija

September in Idrija, Slovenia, is marked by significant rainfall, with 194 mm (7.6 in) of precipitation over 13 days. This makes it one of the wetter months, continuing the trend of high precipitation that begins in late spring and peaks in late summer. As summer transitions to autumn, the increased rainfall reflects the shifting weather patterns, setting the stage for the cooler months ahead. Notably, September's precipitation not only surpasses the previous months of June, July, and August, but also closely aligns with November's totals, highlighting a pronounced shift in weather as the year progresses. This trend suggests that while May may be the wettest month, September delivers a substantial amount of rainfall that is crucial for the region's lush landscapes.

September Precipitation Trends in Idrija

The chart displays monthly precipitation patterns in Idrija, 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 Idrija, September typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec70132103137223128137131194134193169
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Idrija

As summer fades, September in Idrija, Slovenia, sees a subtle shift in humidity, rising to 64% after the drier months of July and August, which recorded humidity levels as low as 63% and 51%, respectively. This slight increase hints at the gradual transition into fall, as the air retains a bit more moisture, contrasting sharply with the winter months ahead, where humidity levels climb significantly, reaching 88% in January and December. Overall, Idrija experiences a wave-like pattern in humidity throughout the year, with a notable peak during the colder months, making September a bridge between the warmth of summer and the approaching chill of autumn.

September Average Humidity in Idrija

This chart illustrates the average monthly humidity levels in Idrija, 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 Idrija 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 Idrija

In September, the UV Index in Idrija, Slovenia strikes a balance with a value of 7, categorizing it as high. As summer gives way to autumn, sun exposure is still significant but requires a bit more caution. With a burn time of approximately 25 minutes, it’s essential to protect your skin during this month, especially as the weather remains pleasant. Notably, September's UV levels start to decline from the heights reached in June and July, which had very high ratings of 9, but still demand attention to sun safety. For more detailed information on the UV Index throughout the year, visit Idrija UV Index.

Maximum UV Index Levels in Idrija for September

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

In September, Idrija, Slovenia, basks in a delightful 317 hours of sunshine, showcasing the gradual transition from summer's warmth to autumn's embrace. Following the sun-drenched heights of July and June, which dazzle with over 400 hours each, September still benefits from lingering summer rays, albeit with a notable decrease. This month’s sunny hours mark a gentle decline as the days grow shorter, compared to the peak of May and June, but still provide ample opportunity to explore Idrija's charming landscapes. As October approaches with its 282 hours of sunshine, the shift in seasonal light is palpable, inviting residents and visitors alike to savor the last golden touches of September before autumn settles in.

Monthly Sunshine Duration in Idrija: September Highlighted

The September sunshine duration represents the total number of hours Idrija 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.
JanFebMarAprMayJunJulAugSepOctNovDec180h222h307h336h360h409h426h392h317h282h215h206h
Data source: Idrija September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Idrija During September

In Idrija, Slovenia, the likelihood of sunny weather in September stands at a promising 49%, aligning with the summer months as the sun continues to shine brightly. This percentage is notably an improvement compared to the cooler months earlier in the year; for instance, January offers just 24% sunshine, while April dips down to 34%. As the fall season unfolds, September maintains a favorable position, similar to the sunniest summer months of July and August, which both sit at 45%. This trend indicates that visitors can expect a pleasant blend of still-warm weather and longer sunny spells, making it an ideal time for outdoor activities and exploration in the picturesque landscapes of Idrija.

Percentage of Sunny Days in September in Idrija

The chart illustrates the percentage of sunny days in Idrija 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 Idrija experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec25%37%56%34%32%49%45%45%50%38%29%33%
Data source: Idrija September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Idrija in September

As the summer sun begins to wane, September in Idrija, Slovenia, sees daylight gently tapering to about 12 hours. This month marks a transitional phase, where the long, golden days of summer give way to the crisp beginnings of autumn. After basking in 15 hours of daylight during June and July, residents now experience a noticeable shift, reminiscent of the gradual reduction observed from bright May through to the shorter days of October. The decrease highlights a rhythmic cycle of nature, inviting both reflection and appreciation as the landscape transforms into vibrant hues of fall, all under the diminishing yet enchanting light of early autumn.

Average Daylight Hours in Idrija for September

The chart illustrates the variation in daylight duration in Idrija 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 20m11h 56m13h 34m14h 58m15h 40m15h 18m14h 3m12h 29m10h 52m9h 26m8h 41m
Data source: Idrija daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Idrija

In Idrija, Slovenia, the September winds gently whisper with an average speed of 1.7 m/s (4 mph), mirroring the calmness of the preceding summer months. This subtle breeze not only provides a transition into the cooler autumn air but also continues a trend of relatively low wind speeds observed throughout the summer. As the year progresses into October, winds pick up slightly to 2.4 m/s (5 mph), hinting at the seasonal shift. The consistent wind patterns of 1.7 m/s in September reflect the serene charm of Idrija, where nature’s rhythm unfolds quietly yet undeniably, offering a perfect backdrop for both contemplation and exploration.

Average September Wind Speed in Idrija

The chart displays monthly wind speed patterns in Idrija, 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.
JanFebMarAprMayJunJulAugSepOctNovDec1.92.11.92.01.91.61.71.71.7 m/s2.42.21.7
Data source: Idrija September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Idrija Compares to Other Months

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

September and January present stark contrasts in weather. In September, temperatures range from a mild 2°C (36°F) at night to a warm 29°C (85°F) during the day, making it an ideal time for outdoor activities. This month also sees higher precipitation, with around 194 mm (7.6 in) falling over 13 days, coupled with a moderate humidity level of 64%. In contrast, January features much colder temperatures, dropping as low as -12°C (11°F) at night and averaging just 1°C (34°F) during the day. Precipitation is significantly lower at 70 mm (2.8 in) over only 7 days, but humidity rises to 88%, creating a damp chill in the air. For more detailed insights into January weather, you can visit Idrija weather in January.

Comparing September and February weather reveals notable differences in temperature and overall climate. In September, temperatures range from a minimum of 2°C (36°F) to a maximum of 29°C (85°F), with an average of 16°C (60°F), while February features a much colder range, with minimums plunging to -12°C (12°F) and an average of only 3°C (38°F), peaking at 19°C (66°F). September also sees higher temperatures and moderate humidity at 64%, whereas February experiences a significant increase in humidity to 82%. Additionally, September receives more precipitation, totaling 194 mm (7.6 in) over about 13 days, compared to February's 132 mm (5.2 in) over 11 days. For a closer look at February's weather patterns, you can visit Idrija weather in February.

September and March present strikingly different weather patterns. In September, temperatures can range from a cool 2°C (36°F) at night to a warm 29°C (85°F) during the day, with an average of 16°C (60°F). In contrast, March experiences much colder temperatures, dipping as low as -17°C (2°F) at night and only reaching a maximum of 21°C (71°F) during the day, with an average of 6°C (42°F). Precipitation also varies, with September receiving 194 mm (7.6 in) over 13 days, while March has lower precipitation at 103 mm (4.1 in) over 11 days. Additionally, March tends to be slightly more humid, with humidity levels at 73%, compared to September's 64%. For more detailed insights, you can check Idrija weather in March.

When comparing the weather in September and April, several notable differences emerge. September boasts a warmer average temperature of 16°C (60°F) with maximums reaching 29°C (85°F), while April is cooler, with an average of just 10°C (50°F) and maximums of 25°C (78°F). Precipitation is higher in September at 194 mm (7.6 in) over 13 days, compared to April's 137 mm (5.4 in) over 12 days. Additionally, April experiences slightly higher humidity at 73%, compared to September's 64%. For a more detailed look at April weather, you can refer to Idrija weather in April.

In September, temperatures range from a chilly 2°C (36°F) at their lowest to a warm 29°C (85°F) at their peak, resulting in an average of 16°C (60°F). The month experiences about 194 mm (7.6 in) of precipitation over 13 days, with a relative humidity of 64%. In contrast, May sees slightly cooler temperatures with a minimum of 1°C (35°F) and a maximum of 26°C (79°F), averaging around 14°C (57°F). It is generally wetter, with 223 mm (8.8 in) of rain over 21 days and higher humidity at 70%. For more details, check out Idrija weather in May.

When comparing the weather in June and September, it's clear that June generally offers warmer temperatures, with minimums around 6°C (43°F) and maximums peaking at 35°C (95°F), compared to September's cooler range of 2°C (36°F) to 29°C (85°F). The average temperature in June is higher at 19°C (67°F), while September averages a cooler 16°C (60°F). Additionally, June experiences less precipitation, with 128 mm (5.0 in) over 12 days, in contrast to September's 194 mm (7.6 in) across 13 rain-soaked days. Both months have similar humidity levels, with June at 69% and September slightly lower at 64%. For a detailed look at how June weather unfolds in Idrija, explore Idrija weather in June.

When comparing the weather in September and July, September tends to be cooler with minimum temperatures dropping to 2°C (36°F) and an average of 16°C (60°F), while July features warmer conditions with minimum temperatures around 10°C (50°F) and an average of 20°C (69°F). The maximum temperatures in July reach up to 33°C (93°F), significantly higher than September's peak of 29°C (85°F). Rainfall is more prevalent in September, with 194 mm (7.6 in) of precipitation over 13 days compared to July's 137 mm (5.4 in) over 16 days. Both months share similar humidity levels, with September at 64% and July at 63%. For detailed insights into July's weather, you can check Idrija weather in July.

In comparing the weather between August and September, we observe notable differences in temperature and precipitation. September experiences a broader temperature range, with a minimum of 2°C (36°F) and a maximum of 29°C (85°F), leading to an average of 16°C (60°F). In contrast, August tends to be much warmer, featuring a minimum of 9°C (48°F) and a maximum of 34°C (93°F), with an average temperature of 21°C (69°F). Precipitation is also more pronounced in September, totaling 194 mm (7.6 in) over 13 days, compared to August's 131 mm (5.2 in) over 15 days. Additionally, humidity levels rise in September to 64%, while August maintains a lower humidity of 51%. For more detailed insights into August's weather, visit Idrija weather in August.

September and October present a noticeable transition in weather conditions. September typically features a wider temperature range with minimums around 2°C (36°F) and maximums reaching 29°C (85°F), averaging a comfortable 16°C (60°F). However, it also brings a fair amount of rainfall, accumulating 194 mm (7.6 in) over about 13 days, with a humidity level of 64%.

In contrast, October cools down significantly, with minimum temperatures dropping to 0°C (33°F) and maximums peaking at 23°C (73°F), resulting in an average of 11°C (52°F). Though precipitation decreases to 134 mm (5.3 in) over 11 days, the humidity increases to 83%, making the air feel much wetter. For more detailed insights, you can check out Idrija weather in October.

In comparing the weather of September and November, we see a notable shift in temperature and humidity. September experiences milder temperatures, ranging from a minimum of 2°C (36°F) to a maximum of 29°C (85°F), with an average of 16°C (60°F). In contrast, November brings cooler conditions, with temperatures dipping to a minimum of -6°C (22°F) and averaging only 6°C (44°F). While both months receive similar precipitation levels, with about 194 mm (7.6 in) over 13 days, November's humidity is considerably higher at 89% compared to September's 64%. For more detailed information about the weather in November, you can check Idrija weather in November.

September and December exhibit contrasting weather patterns. In September, temperatures range from a minimum of 2°C (36°F) to a warm average of 16°C (60°F), peaking at 29°C (85°F). This month sees considerable rainfall, with 194 mm (7.6 in) over 13 days and a moderate humidity level of 64%. In contrast, December experiences much colder temperatures, with a minimum of -11°C (13°F) and an average of just 2°C (36°F), reaching a maximum of 12°C (55°F). Although precipitation is slightly lower at 169 mm (6.7 in) over 11 days, humidity rises significantly to 88%. For more detailed insights, you can refer to Idrija weather in December.

Compare Idrija's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Idrija

As September ushers in the transition from the heat of summer to the cooler embrace of autumn, Idrija experiences a striking array of weather conditions. With average temperatures dipping to a comfortable 16°C while still reaching peaks of 29°C, the month presents a delightful balance for outdoor enthusiasts. Unlike the drier months preceding it, September often sees a notable increase in rainfall, totaling 194 mm over approximately 13 days, contributing to a refreshing ambiance. This increase in precipitation and humidity, sitting at 64%, adds to the lush landscapes that characterize Idrija this time of year. For those interested in exploring the unique weather patterns of this enchanting region, more information can be found at Idrija Climate.