Last updated: August 27, 2025
September in Portoroz, Slovenia offers a delightful transition from summer to autumn, with maximum temperatures reaching up to 28°C (82°F) and an average of 22°C (71°F), providing warm days for visitors. Although the minimum temperature can drop to 14°C (57°F), the overall climate remains pleasant. However, prepare for some rainfall, as the month sees an average precipitation of 171 mm (6.7 in) across approximately 10 days, maintaining a humidity level of 64%. Enjoy the beautiful landscapes and vibrant atmosphere while embracing the rich and changing weather of early autumn.
September in Portorož, Slovenia, marks a delightful transition into early autumn, with temperatures reflecting this change. The month begins with minimums around 14°C (57°F), gradually rising to an average of 22°C (71°F) and peaking at a comfortable 28°C (82°F). This creates an inviting atmosphere for outdoor activities, as the warmth lingers from the summer months. The weather is perfect for leisurely strolls along the scenic coastline or enjoying a meal al fresco. Compared to the hotter heights of July and August, September offers a more temperate climate, making it a favorite for those seeking a blend of warmth and comfort as the summer crowd begins to draw down.
September in Portorož, Slovenia, is marked by a significant shift in weather as the summer heat begins to wane. With 171 mm (6.7 in) of precipitation spread across 10 days, it becomes the month with the highest rainfall of the year, indicating a rapid transition into the wetter autumn season. This uptick in precipitation follows a relatively dry summer, where rainfall hovered below 60 mm in both July and August. As the gardens and landscapes soak in the abundant moisture, September sets the stage for the lush, green vistas that characterize the following months. This increase not only rejuvenates the local flora but also signals a change in the seasonal rhythm, preparing residents and nature alike for the cool and damp days ahead.
In September, Portoroz, Slovenia begins to transition from the warm summer months, with humidity levels rising to 64%. This marks a noticeable increase from August's 51%, reflecting the gradual onset of autumn. The trend for the year shows that humidity in Portoroz peaks in the winter months, with January and February hovering around 88% and 82% respectively. As the seasons shift, the data highlights a significant drop during the summer, reaching its lowest point of 63% in July. September's humidity sits comfortably between the summer's dryness and the wetter conditions of fall, signaling a return to the lush, refreshing qualities of the Adriatic coastline.
As summer wanes in September, Portoroz, Slovenia, experiences a slight decrease in the UV Index, reaching a value of 7, which falls into the high exposure category. This marks a transition from the peak summer months, where the UV Index reached a maximum of 9 in both June and July. Despite the drop, sun seekers should remain mindful, as burn time remains at 25 minutes for unprotected skin. Compared to earlier months, like May and August, where the index was 8, September offers a more moderate yet still significant solar intensity, inviting residents and travelers alike to enjoy the outdoors responsibly. For detailed insights and daily updates, visit the Portoroz UV Index.
UV Risk Categories
As September unfolds in Portoroz, Slovenia, visitors can bask in the warm embrace of 326 hours of sunshine, marking the transition from the vibrant summer months into the gentle embrace of autumn. This sunny interlude follows a peak in July, which boasts a remarkable 430 hours of golden rays, and gracefully descends into the cozier brightness of October with 293 hours. The trend showcases a cooling yet welcoming environment, with September’s sunshine offering plenty of opportunities for outdoor exploration and relaxation by the Adriatic. While the days may be shortening, the lingering warmth of summer casts a golden hue over the start of fall, making it a delightful time to experience the beauty of this coastal gem.
In Portoroz, Slovenia, the likelihood of enjoying sunny weather in September stands at a promising 59%, making it one of the more favorable months for sun-seekers. This figure reflects a notable trend; as summer progresses, the chances of sunshine gradually increase, peaking in August with 62% before slightly tapering off as autumn approaches. September’s sunshine probability holds strong, promoting pleasant days ideal for outdoor activities and relaxation by the Adriatic Sea. Comparatively, this month offers significantly brighter prospects than the winter months, where chances of sun dip to the low 30s. Thus, visitors to Portoroz in September can anticipate a delightful blend of late summer warmth and sunny skies.
As September arrives in Portorož, Slovenia, daylight begins to wane, offering approximately 12 hours of sunlight each day. This transition marks a gradual retreat from the summer's peak, where June and July basked in a generous 15 hours of daylight. Following the vibrant summers, August also holds on to 14 hours, but as autumn sets in, the daylight decreases, reflecting the natural ebb and flow of the seasons. Interestingly, while the long light-filled days are a hallmark of spring and summer—April presenting 13 hours and May offering 14 hours—September serves as a gentle reminder that cozy evenings are just around the corner, paving the way to the shorter days of October with just 10 hours of light.
In September, the winds in Portorož, Slovenia exhibit a gentle rhythm, with an average speed of 3.4 m/s (8 mph), mirroring the calmer breezes of July and August. As summer wanes, the atmosphere remains relaxed, inviting visitors to bask in the moderate conditions. This month serves as a transition, as winds build slightly towards the end of the season, leading into the brisk gusts of October, which reaches 5.0 m/s (11 mph). The gradual increase in wind speeds from summer into autumn reveals nature's subtle shift, enhancing the tranquil allure of the coastal town while hinting at the dynamic changes just ahead.
Weather in Portoroz varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Portoroz, focusing on differences in temperature, rainfall, humidity, and UV levels.
September offers a mild and pleasant climate, with temperatures ranging from a minimum of 14°C (57°F) to a comfortable maximum of 28°C (82°F) and an average of 22°C (71°F). However, this month also experiences a significant amount of rain, totaling 171 mm (6.7 in) across about 10 days, coupled with a moderate humidity level of 64%. In contrast, January presents a starkly different landscape. Temperatures drop considerably, with a minimum of -3°C (27°F) and a maximum of just 13°C (56°F), averaging around 7°C (46°F). Despite January having less overall rainfall at 58 mm (2.3 in) across 7 days, the humidity is notably higher at 88%, contributing to a crisp and cold atmosphere. For more detailed information, you can check Portoroz weather in January.
When comparing the weather in September and February, there is a stark contrast in temperatures and conditions. September boasts a mild climate with average temperatures around 22°C (71°F) and maximums peaking at 28°C (82°F), while February sees much colder weather, with averages only reaching 8°C (47°F) and maximums capping at 13°C (56°F). Additionally, September experiences higher precipitation at 171 mm (6.7 in) across about 10 days, although February still sees considerable rainfall, totaling 106 mm (4.2 in) over 11 days. The humidity levels also differ, with February being more humid at 82% compared to September’s 64%. For more information about February weather specifically, visit Portoroz weather in February.
September and March exhibit contrasting weather patterns. September enjoys a mild climate with temperatures ranging from a minimum of 14°C (57°F) to a maximum of 28°C (82°F), accompanied by an average temperature of 22°C (71°F). In contrast, March presents a much cooler atmosphere, with temperatures dipping to a minimum of -3°C (27°F) and an average of only 10°C (50°F), reaching a maximum of 16°C (62°F). Additionally, September experiences significantly higher precipitation, totaling 171 mm (6.7 in) over about 10 days, while March has a milder 57 mm (2.3 in) of rainfall across 7 days. The humidity is slightly higher in March at 73% compared to 64% in September. For more information about March weather, visit Portoroz weather in March.
When comparing the weather in September and April, it's clear that September enjoys a warmer climate. With average temperatures ranging from a minimum of 14°C (57°F) to a maximum of 28°C (82°F), it significantly outpaces April, which sees milder temperatures between 5°C (42°F) and 20°C (68°F). Additionally, September experiences more rainfall, totaling 171 mm (6.7 in) over approximately 10 days, while April has 86 mm (3.4 in) of precipitation over 8 days. Humidity levels are slightly higher in April at 73%, compared to September's 64%. For more detailed insights into April weather specifically, you can visit Portoroz weather in April.
The weather in September tends to be warmer than in May, with average temperatures reaching 22°C (71°F) compared to May's average of 17°C (64°F). September boasts maximum temperatures of 28°C (82°F), while May peaks at 24°C (76°F). However, September also experiences more precipitation, with 171 mm (6.7 in) falling over 10 days, compared to May's 105 mm (4.2 in) over 13 days. Humidity levels in May are slightly higher at 70%, compared to September's 64%. For a more detailed look at May weather, you can check Portoroz weather in May.
In comparing the weather of September and June, we notice several distinct differences. September experiences a slightly wider temperature range, with average temperatures around 22°C (71°F) and maximums reaching up to 28°C (82°F), compared to June, which averages 23°C (73°F) and peaks at 30°C (86°F). However, September sees significantly more precipitation, with 171 mm (6.7 in) falling over 10 days, compared to June's 68 mm (2.7 in) over just 5 days. Additionally, September's humidity is relatively lower at 64%, while June tends to be a bit more humid at 69%. For more detailed information, you can check Portoroz weather in June.
September weather tends to be cooler than that of July, with average temperatures ranging from a minimum of 14°C (57°F) to a maximum of 28°C (82°F), compared to July’s warmer range of 20°C (68°F) to 29°C (85°F). Additionally, September experiences significantly higher precipitation, with 171 mm (6.7 in) over approximately 10 days, while July sees only 49 mm (1.9 in) across about 6 days of rain. Both months have similar humidity levels, hovering around 64% in September and 63% in July, which creates a comfortable atmosphere. To learn more about the weather specifics in July, you can check Portoroz weather in July.
In comparing the weather between September and August, we see a notable shift in temperatures and precipitation patterns. September experiences a cooler minimum temperature of 14°C (57°F), with an average of 22°C (71°F) and a maximum of 28°C (82°F). In contrast, August boasts warmer conditions, starting with a minimum of 17°C (63°F), an average of 26°C (78°F), and peaking at 30°C (87°F). Additionally, September is considerably wetter, receiving 171 mm (6.7 in) of precipitation over 10 days, compared to August's 58 mm (2.3 in) over just 6 days. The humidity also rises significantly in September, reaching 64%, compared to August's more comfortable 51%. For more information on the August climate, you can check out Portoroz weather in August.
September tends to be warmer than October, with average temperatures ranging from a minimum of 14°C (57°F) to a maximum of 28°C (82°F), while October sees cooler temperatures, with a minimum of 11°C (52°F) and a maximum of 23°C (73°F). Additionally, September experiences higher overall precipitation at 171 mm (6.7 in) over 10 days, compared to October's more moderate 100 mm (4.0 in) also over 10 days. Humidity levels in October are notably higher at 83%, compared to September's 64%, contributing to a distinct seasonal shift. For more details, check out Portoroz weather in October.
September and November display a significant contrast in weather patterns. In September, temperatures are considerably warmer, with averages around 22°C (71°F) and a maximum reaching 28°C (82°F). The month experiences moderate precipitation, totaling 171 mm (6.7 in) over about 10 days, accompanied by a relative humidity of 64%. In contrast, November brings much cooler temperatures, with average highs of just 13°C (56°F) and minimums dropping to 6°C (42°F). Additionally, November sees increased precipitation of 183 mm (7.2 in) over 13 days and higher humidity at 89%. This shift underscores the transition from the warmth of early autumn to the chill of late fall. For more details, check Portoroz weather in November.
The weather in September is generally milder and more pleasant, with average temperatures reaching around 22°C (71°F) and a maximum of 28°C (82°F). In contrast, December brings significantly cooler conditions, with average temperatures falling to just 10°C (50°F) and a high of 16°C (60°F). While September experiences more moderate humidity at 64%, December's humidity rises to 88%, contributing to a chillier atmosphere. Precipitation is also noteworthy in both months, with September seeing 171 mm (6.7 in) over 10 days, compared to December’s 150 mm (5.9 in) over 13 days. For more information about December weather, you can visit Portoroz weather in December.
As summer transitions into autumn, September's weather in Portorož offers a delightful blend of warmth and refreshing breezes. With average temperatures hovering around a comfortable 22°C (71°F), the days are still pleasantly warm, yet noticeable shifts in the air signal the impending cooler months. Unlike the sweltering peak of summer, September also brings increased precipitation, with around 10 rainy days throughout the month, enhancing the lush landscape. This combination of moderating temperatures and occasional rain creates an inviting atmosphere for both locals and travelers. For a detailed understanding of what to expect in Portorož year-round, check out Portoroz Climate.