September Weather in Iasi, Romania

Last updated: August 27, 2025

September in Iași, Romania is characterized by a delightful transition from summer's heat to the cooler embrace of autumn. With maximum temperatures soaring to 34°C (94°F), the month can still feel quite warm, while an average temperature of 18°C (65°F) presents a pleasant balance. As the season shifts, the temperature can dip to a minimum of 3°C (37°F) during the nights. Although 28 mm (1.1 in) of precipitation falls over just 6 days, the air remains relatively moist with an average humidity of 62%. This blend of warmth and occasional rainfall makes September an intriguing time to explore the vibrant landscapes and rich cultural experiences that Iași has to offer.

September Temperature in Iasi

In September, Iasi, Romania welcomes the onset of autumn with a refreshing shift in temperatures. With minimums averaging around 3°C (37°F) and daily highs peaking at a warm 34°C (94°F), the month presents a delightful mix of summer's lingering warmth and the coolness of fall. The average temperature settles at a comfortable 18°C (65°F), making it an inviting time for outdoor activities and exploration. As the month progresses, temperatures begin to gently decline, hinting at the cooler days ahead. This transitional period offers an ideal climate for enjoying the vibrant autumnal scenery and cultural events that the region is known for.

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

The chart illustrates September temperature patterns in Iasi, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Iasi, 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).
JanFebMarAprMayJunJulAugSepOctNovDec303441526270727364544335
Data source: Temperature data for Iasi 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 Iasi

As September arrives in Iasi, Romania, the city experiences a pleasant shift in weather marked by a notable pattern in precipitation. With an average rainfall of 28 mm (1.1 in) over 6 days, September is characterized by a mild decrease in moisture compared to the summer months, particularly June, which sees the highest rainfall at 97 mm (3.8 in). This gradual tapering off signals the transition into autumn, as rainfall starts to stabilize. Interestingly, while precipitation tapers off, it remains consistent, reflecting a typical early autumn climate. The following months, particularly October and November, maintain similar levels of precipitation, suggesting a steady and balanced transition in weather as the year winds down.

September Precipitation Trends in Iasi

The chart displays monthly precipitation patterns in Iasi, 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 Iasi, September typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec233638346897624128333153
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Iasi

As summer gives way to autumn, September in Iasi, Romania, experiences a moderate humidity level of 62%, a noticeable rise from the drier August, which recorded 56%. This transition reflects a broader pattern throughout the year, where the humidity gradually decreases from the frigid winter months that peak at 92% in January, reaching its lowest point in August. As the seasons shift, you can anticipate humidity levels bouncing back in October to 80%, hinting at the onset of wetter conditions. Overall, September serves as a bridge, gently ushering in the moist air of fall while still holding onto some summer warmth.

September Average Humidity in Iasi

This chart illustrates the average monthly humidity levels in Iasi, 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 Iasi is approximately {2}%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec92%88%86%79%73%73%69%56%62%81%89%90%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Iasi

As summer fades into autumn, September in Iasi, Romania experiences a notable shift in UV exposure. With a UV Index of 7, classified as high, sun protection becomes essential once again after the peak intensity of the summer months. This heightened level indicates a burn time of 25 minutes, giving residents a little more leeway compared to the preceding months when the index soared to 9 in July and June. Though September's UV Index is lower than in the height of summer, it remains important to stay vigilant against harmful rays. For more details on daily trends and safety measures, visit Iasi UV Index.

Maximum UV Index Levels in Iasi for September

The chart shows the monthly maximum UV Index (UVI) for Iasi 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 Iasi typically reaches {2}, which falls under the {3} exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec235689987432
Data source: Iasi 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 Iasi

As summer gracefully transitions to autumn, September in Iași, Romania, offers a delightful average of 335 sunshine hours. This marks a gentle decline from the sun-drenched peak of July, which boasts 431 hours, capturing the essence of the warm season. Interestingly, September still enjoys a generous share of daylight compared to the chilly winter months ahead, showcasing a clear trend of decreasing sunshine as the year progresses. With each passing month from May through September revealing a steady peak, the gradual shift towards October’s 284 hours highlights the region's vibrant autumn charm, inviting residents and visitors alike to relish the crisp air and golden hues before winter's embrace arrives.

Monthly Sunshine Duration in Iasi: September Highlighted

The September sunshine duration represents the total number of hours Iasi 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.
JanFebMarAprMayJunJulAugSepOctNovDec154h214h297h347h399h411h431h409h335h284h198h157h
Data source: Iasi September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Iasi During September

In Iasi, Romania, the likelihood of enjoying sunny weather in September stands at 43%, reflecting a pleasant transition from the summer's peak. As the seasons shift, this percentage shows a notable drop from the brighter days of August, which boasts a 56% chance of sunshine. However, compared to the earlier months of the year, September still offers a favorable chance of clear skies. The sunlit days of July and August set a high bar, but September maintains an appealing balance before welcoming the cooler, cloudier months ahead. Ultimately, it’s a moment where summer's warmth lingers just enough, making September in Iasi a charming time for outdoor activities under the sun.

Percentage of Sunny Days in September in Iasi

The chart illustrates the percentage of sunny days in Iasi 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 Iasi experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec29%33%37%47%40%37%54%56%43%50%37%15%
Data source: Iasi September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Iasi in September

As summer fades into autumn, September in Iași, Romania, offers a gentle transition in daylight, providing approximately 12 hours of sunlight. This month marks a noticeable decrease from the 14 hours typically enjoyed in August, signaling the shift towards shorter days. Interestingly, the daylight duration in September still retains the warmth of the season, echoing the 15 hours seen in the peak months of June and July. As the year progresses, daylight dwindles, gradually dropping to 10 hours in October and further to 8 hours by December. This rhythmic ebb and flow of sunlight not only highlights the changing seasons but also captivates the essence of time in Iași, inviting both locals and visitors to savor each moment beneath the softening rays of autumn.

Average Daylight Hours in Iasi for September

The chart illustrates the variation in daylight duration in Iasi throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec8h 56m10h 16m11h 55m13h 38m15h 6m15h 51m15h 27m14h 9m12h 30m10h 49m9h 18m8h 31m
Data source: Iasi daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Iasi

As September rolls into Iasi, Romania, the average wind speed settles at a gentle 2.6 m/s (6 mph), creating a calm yet invigorating atmosphere. This slight uptick from the summer months reflects a transition in the season, where the whispering winds begin to carry the crispness of autumn. Following a lull in July and August with the same modest breeze of 2.4 m/s (5 mph), September offers a refreshing shift, indicating nature's preparation for the cooler months ahead. Interestingly, as the year progresses into October and November, wind speeds show a slight increase, suggesting a potential buildup of chill and change, reinforcing the notion that Iasi's winds are not just elements of the weather, but harbingers of the shifting seasons.

Average September Wind Speed in Iasi

The chart displays monthly wind speed patterns in Iasi, 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.
JanFebMarAprMayJunJulAugSepOctNovDec2.73.03.22.53.03.12.42.42.6 m/s2.52.93.2
Data source: Iasi September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Iasi Compares to Other Months

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

September and January present stark contrasts in weather conditions. In September, temperatures range from a cool 3°C (37°F) at night to a warm average of 18°C (65°F), peaking at a sweltering 34°C (94°F) during the day, while experiencing relatively low precipitation of 28 mm (1.1 in) over six days and a moderate humidity of 62%. In contrast, January brings much colder temperatures, with lows plummeting to -18°C (0°F) and an average temperature of -1°C (30°F), only reaching a maximum of 13°C (56°F). January also sees slightly less precipitation at 23 mm (0.9 in) but experiences a significantly higher humidity of 92%, contributing to the chilly atmosphere. For more details on January weather, you can visit Iasi weather in January.

September and February present stark contrasts in weather. In September, temperatures typically range from a mild minimum of 3°C (37°F) to a warm maximum of 34°C (94°F), with an average of 18°C (65°F). The month experiences about 28 mm (1.1 in) of precipitation over approximately 6 days, accompanied by a humidity level of 62%. In contrast, February's climate is significantly colder, with temperatures dipping to a minimum of -20°C (-4°F) and peaking at a maximum of 18°C (65°F), averaging around 1°C (34°F). This month also sees slightly higher precipitation at 36 mm (1.4 in) over 7 days, but the humidity is notably higher at 88%. For more detailed insight, you can check Iasi weather in February.

When comparing the weather in September and March, notable contrasts emerge. September boasts a much warmer climate, with average temperatures around 18°C (65°F) and highs reaching up to 34°C (94°F), while March sees significantly cooler temperatures, averaging just 5°C (41°F) and dipping as low as -15°C (5°F). Additionally, September experiences lower humidity at 62% compared to March's 86%, contributing to a more comfortable atmosphere during the autumn month. Precipitation is also more prominent in March, with 38 mm (1.5 in) over nine days, while September records only 28 mm (1.1 in) spread across six days. For a more detailed look at March weather specifically in Iasi, you can check Iasi weather in March.

In comparing the weather of September and April, it's clear that September tends to be warmer and drier. With average temperatures reaching 18°C (65°F), September can see highs peaking at 34°C (94°F) and only experiences 28 mm of precipitation over about six days, while maintaining a humidity level of 62%. In contrast, April is noticeably cooler, with average temperatures around 11°C (52°F) and maximums reaching only 28°C (82°F), yet it is slightly wetter, receiving 34 mm of rain over approximately seven days and with higher humidity at 79%. For more detailed insights about the weather in April, you can check out Iasi weather in April.

In comparing the weather between September and May, we see distinct differences in temperature and precipitation patterns. September boasts a wider temperature range with a minimum of 3°C (37°F), an average of 18°C (65°F), and a maximum of 34°C (94°F), while May features a similar minimum of 3°C (38°F) but lower average temperatures at 16°C (62°F) and a maximum of 30°C (87°F). When it comes to precipitation, September experiences less rainfall, totaling 28 mm (1.1 in) over an average of 6 days, compared to May's significantly higher precipitation of 68 mm (2.7 in) spread over 11 days. Additionally, May has slightly higher humidity at 73% versus September's 62%. For more detailed insights, you can check Iasi weather in May.

In comparing the weather between September and June, September offers a wider temperature range, with minimums dipping to 3°C (37°F) and maximums reaching as high as 34°C (94°F). Averaging 18°C (65°F), it provides a pleasant transition from summer to autumn, accompanied by relatively low precipitation at 28 mm (1.1 in) over six days and moderate humidity at 62%. In contrast, June tends to be warmer, with an average temperature of 21°C (71°F) and maximums of 33°C (91°F). However, it experiences significantly more rainfall, totaling 97 mm (3.8 in) across 14 days, and comes with higher humidity levels at 73%. For more detailed information about the weather in June, you can visit Iasi weather in June.

September and July present distinctly different weather patterns. In September, temperatures range from a minimum of 3°C (37°F) to a maximum of 34°C (94°F), with an average of 18°C (65°F). The month experiences less precipitation, totaling 28 mm (1.1 in) over about 6 days, and maintains a humidity level of 62%. In contrast, July is warmer, with minimum temperatures of 11°C (52°F) and maximums reaching 35°C (96°F), averaging 22°C (73°F). July sees more rainfall, totaling 62 mm (2.4 in) across approximately 9 days, accompanied by a higher humidity of 68%. Overall, September offers cooler temperatures and less humidity compared to the warmer, more humid conditions of July. For more details, check Iasi weather in July.

In comparing the weather of September to August, September generally presents a more varied temperature range, with minimums dipping to 3°C (37°F) and maximums reaching 34°C (94°F), compared to August, which sees minimums of 8°C (46°F) and highs of 37°C (99°F). The average temperature in September is cooler at 18°C (65°F), while August's average sits at a warmer 23°C (74°F). Additionally, September experiences slightly less precipitation, totaling 28 mm (1.1 in) over 6 days, compared to August's 41 mm (1.6 in) over the same number of days. Interestingly, September's humidity is higher at 62%, whereas August has a lower humidity level of 56%. Overall, September offers a transition towards cooler temperatures and less rain compared to the warmer and wetter conditions of August. For more details on August weather, you can visit Iasi weather in August.

September weather features a broader temperature range with minimums reaching 3°C and maximums soaring up to 34°C, resulting in an average temperature of 18°C. The month experiences a moderate level of precipitation at 28 mm over about 6 days, along with a humidity level of 62%. In contrast, October sees a significant drop in average temperatures, with minimums falling to 0°C and maximums capping at 27°C, leading to an average of just 12°C. Precipitation slightly increases to 33 mm over only 4 days, while humidity rises to 80%. For more detailed insights, you can check Iasi weather in October.

September and November present stark contrasts in weather. In September, temperatures can range from a chilly 3°C (37°F) at night to a warm 34°C (94°F) during the day, with an average of 18°C (65°F). This month experiences relatively low humidity at 62% and only 28 mm (1.1 in) of rainfall over six days. In contrast, November brings a significant drop in temperature, with nighttime lows hitting -6°C (21°F) and daytime highs reaching 24°C (76°F), averaging just 6°C (43°F). Additionally, November is characterized by higher humidity at 89% and slightly more precipitation, totaling 31 mm (1.2 in) over the same number of rainy days. For more information, check out Iasi weather in November.

In September, the weather in Iasi is characterized by warmer temperatures, with a minimum of 3°C (37°F) and an average of 18°C (65°F), peaking at a maximum of 34°C (94°F). Precipitation is relatively low, with only 28 mm (1.1 in) expected over approximately 6 days and humidity at a comfortable 62%. In contrast, December brings a significant shift, featuring much colder conditions with temperatures ranging from a minimum of -13°C (8°F) to an average of 2°C (35°F) and a maximum of 16°C (61°F). This month sees increased precipitation at 53 mm (2.1 in) spread over about 11 days, along with higher humidity levels at 90%. For a more detailed overview of December's climate, visit Iasi weather in December.

Compare Iasi's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Iasi

As summer gracefully fades into autumn, September in Iași presents a delightful mix of mild temperatures and occasional rain, distinguishing it from the more extreme seasons. With a comfortable average of 18°C, this month offers a refreshing respite from the sweltering heat of July and August, while the cooler nights hint at the approaching chill of autumn. Although there may be some damp days—with about 28 mm of precipitation over several days—the air remains pleasantly humid at 62%, contributing to the vibrant colors of the landscape. Transitioning between warmer days and cooler evenings makes September a unique time to experience the beauty of Iași. For a detailed look at the city's weather patterns throughout the year, visit Iasi Climate.