Last updated: August 27, 2025
In Irkutsk, Russian Federation, September ushers in a mix of mild to cool weather, with daytime temperatures reaching a pleasant maximum of 26°C (79°F) and dipping to a refreshing average of 11°C (52°F). The temperature can occasionally plunge to a crisp minimum of -1°C (31°F). As autumn approaches, the region experiences about 75 mm (2.9 in) of precipitation over 10 days, contributing to an overall humidity level of 84%. This vibrant transition creates a picturesque landscape, perfect for exploring the natural beauty of Siberia during this enchanting month.
In September, Irkutsk experiences a notable transition as it bids farewell to summer warmth and welcomes the crispness of autumn. With temperatures ranging from a frosty -1°C (31°F) at night to a pleasant 26°C (79°F) during the day, the city showcases a delicate balance between the lingering warmth of summer and the impending chill of winter. The average temperature settles around 11°C (52°F), providing a refreshing escape from the sweltering heat of the previous months. As the foliage begins to change, the vibrant landscapes of Irkutsk offer a stunning backdrop against a backdrop of steadily dropping temperatures, making it a captivating time to explore the city’s rich culture and breathtaking natural beauty.
In September, Irkutsk experiences a notable transition in its weather as the summer warmth begins to wane. With precipitation totaling 75 mm (2.9 in), this month marks a significant decline compared to the peak of the wet season seen in July and August, yet it remains relatively moist. Rainfall occurs on approximately 10 days, balancing the lingering warmth of early autumn with the encroaching chill that heralds the upcoming months. This steady drop in both precipitation volume and number of rain days mirrors the broader trend of decreasing moisture as the region shifts from the lush summer months towards the drier fall season, setting the stage for the crispness of October.
As the summer wanes into September in Irkutsk, the humidity begins to rise again, reaching 84% this month. This marks a noticeable shift from the lower levels experienced during the summer, particularly June's 64% and July's 71%. Following the August peak at 73%, September's humidity indicates a transitional period as the city prepares for the cooler autumn months. Reflecting the seasonal shift, such increases in humidity may feel more pronounced, especially as autumn's chill approaches, reminiscent of January's high of 94%. Overall, September serves as a bridge, highlighting the fluctuation of humidity as the year progresses from the dry warmth of summer to the dampness of the coming winter.
As summer transitions to autumn in Irkutsk, September sees a moderate UV Index of 5, maintaining the cautionary levels established in the months prior. This means while the risk of harm from unprotected sun exposure is moderate, there's still ample opportunity to enjoy outdoor activities safely with appropriate precautions. With a burn time of 30 minutes, it's advisable to seek shade or apply sunscreen for extended periods outside. Compared to the heightened UV levels of summer, this decrease indicates a gradual decline in sun intensity, providing a comfortable middle ground before the cooler months set in. For a detailed understanding of UV exposure throughout the year, visit Irkutsk UV Index.
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As summer gives way to autumn in Irkutsk, September brings a delightful balance of sunshine, averaging 295 hours of daylight. This marks a gentle decline from the sun-drenched months of June and July, which bask in over 370 hours of sunlight. However, unlike the stark drop seen in earlier months, September's hours reflect a relatively mild reduction, continuing the gradual transition initiated in August. The warm vestiges of summer still linger in the air, inviting both locals and travelers to savor the scenic beauty of the region before colder days set in. This month's sunshine lays the groundwork for a cozy autumn, with the promise of a picturesque landscape painted in hues of orange and gold.
In September, Irkutsk experiences a 40% chance of sunny weather, aligning with the moderately optimistic trend of late summer. This percentage mirrors the sunshine likelihood of the preceding months, August and April, while significantly higher than the bleak winters of January and February. As the city transitions into autumn, the prospects for sunshine begin to rise, making September an appealing time for those looking to enjoy the region's natural beauty before the colder months set in. With a steady increase leading into October, when sunny days reach about 53%, September serves as a promising bridge to the vibrant autumn landscape, offering just the right mix of mild warmth and occasional sun.
In September, Irkutsk experiences a transition as daylight begins to wane, offering approximately 12 hours of sun. This marks a gentle decline from the summer peak of 16 hours in June and July, as the days gradually shorten. Following the long, bright days of summer, September's daylight still provides a generous amount of sun, encouraging a continuation of outdoor activities. The month serves as a bridge, heralding the approach of autumn while retaining the warmth of late summer, before settling into the deeper twilight of October with just 10 hours of daylight. As the seasons shift, these changing light patterns beautifully illustrate nature's rhythm in this northern locale.
As summer transitions to autumn, September in Irkutsk experiences a gentle shift in wind patterns, with an average speed of 2.8 m/s (6 mph). This slight increase from August's 2.7 m/s reflects a trend of fluctuating winds as the seasons change. Notably, as we move through the year, wind speeds generally trend upwards from winter's calm, reaching their peak in May before tapering off in the warmer months. The steady September breeze serves as a reminder of the coming colder months, with winds typically calming down again by October. This rhythm of wind throughout the year mirrors the natural ebb and flow of Irkutsk’s climate, setting the stage for the crisp autumn days ahead.
Weather in Irkutsk varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Irkutsk, focusing on differences in temperature, rainfall, humidity, and UV levels.
September and January present strikingly contrasting weather conditions. In September, temperatures range from a cool -1°C (31°F) at night to a comfortable 26°C (79°F) during the day, with an average of 11°C (52°F). The month experiences around 75 mm (2.9 in) of precipitation over 10 days, accompanied by a humidity level of 84%. In contrast, January plunges into severe cold, with minimum temperatures dipping to -41°C (-41°F) and an average temperature of -19°C (-1°F), peaking at just -5°C (24°F). This month sees significantly lower precipitation at 12 mm (0.5 in) over a mere 4 days, but humidity is higher at 94%. For more details about January weather, check out Irkutsk weather in January.
September and February present stark contrasts in weather conditions. In September, temperatures range from a minimum of -1°C (31°F) to a comfortable maximum of 26°C (79°F), with an average temperature of 11°C (52°F). The month experiences 75 mm (2.9 in) of precipitation over about 10 days, while humidity remains relatively high at 84%. In contrast, February is characterized by frigid temperatures, with a minimum chilling at -40°C (-39°F) and a maximum of only 5°C (41°F), leading to an average of -16°C (3°F). Precipitation is sparse, totaling just 11 mm (0.4 in) over 4 days, coupled with a striking 90% humidity level. For more details on the harsh weather conditions during this month, visit Irkutsk weather in February.
September and March present stark contrasts in weather. In September, temperatures range from a chilly -1°C (31°F) at night to a warm 26°C (79°F) during the day, averaging around 11°C (52°F). The month experiences moderate rainfall of 75 mm (2.9 in) over approximately 10 days, with humidity levels at 84%. In contrast, March is significantly colder, with nighttime temperatures plunging to -30°C (-22°F) and daytime highs reaching just 12°C (54°F), resulting in an average of -5°C (23°F). Precipitation is minimal at 16 mm (0.6 in) over about 4 days, and humidity is slightly lower at 81%. For a more detailed look at the weather during this month, check out Irkutsk weather in March.
In comparing the weather of September and April, we observe notable differences in temperature and precipitation. September boasts a wider temperature range, with minimums at -1°C (31°F), average highs around 26°C (79°F), and an average temperature of 11°C (52°F). This month experiences 75 mm (2.9 in) of rainfall over approximately 10 days, accompanied by relatively high humidity at 84%. In contrast, April's temperatures are lower, ranging from a minimum of -11°C (13°F) to maximums of 28°C (82°F), with an average of only 4°C (39°F). Rainfall is considerably less, at 19 mm (0.8 in) over about 6 days, and the humidity level is more moderate at 73%. For further details, you can check Irkutsk weather in April.
In comparing the weather of September and May, September features a milder temperature range, with a minimum of -1°C (31°F) and a maximum of 26°C (79°F), while May has slightly cooler extremes, starting at -4°C (24°F) and peaking at a warmer 31°C (89°F). Despite May's higher maximum temperature, it has a lower average temperature of 10°C (50°F) compared to September's 11°C (52°F). Precipitation levels are also different; September experiences 75 mm (2.9 in) of rainfall over 10 days, whereas May has only 48 mm (1.9 in) over 11 days, contributing to the more humid atmosphere of September at 84% compared to May's 67%. For a closer look at May's weather specifics, you can visit Irkutsk weather in May.
When comparing the weather in September and June, significant differences can be observed. September experiences a wider temperature range, with a minimum of -1°C (31°F) and a maximum of 26°C (79°F), while June has milder temperatures, ranging from a minimum of 2°C (37°F) to a maximum of 33°C (92°F). Additionally, the average temperature in June is considerably warmer at 16°C (61°F) compared to September’s average of 11°C (52°F). Precipitation is more abundant in September, totaling 75 mm (2.9 in) over approximately 10 days, compared to June’s 47 mm (1.8 in) during the same number of days. Humidity levels also differ, with September being much more humid at 84%, as opposed to June’s cooler and less humid atmosphere, which sits at around 64%. For more specific details about June’s weather, you can visit Irkutsk weather in June.
When comparing the weather in September to July, notable differences emerge in both temperature and precipitation. September experiences a broader temperature range, with minimums dipping to -1°C (31°F) and maximums reaching 26°C (79°F), while the average temperature stands at 11°C (52°F). In contrast, July is generally warmer, with minimum temperatures of 8°C (46°F), maximums of 32°C (90°F), and an average of 19°C (66°F). Rainfall is also more prominent in July, totaling 96 mm (3.8 in) over 12 days, compared to September’s 75 mm (2.9 in) spread across 10 days. Additionally, September has a higher humidity level at 84%, compared to July's relative humidity of 71%. For a comprehensive overview of July weather in Irkutsk, you can visit Irkutsk weather in July.
September weather in Irkutsk exhibits cooler temperatures compared to August, with minimums dropping to -1°C (31°F) and an average of 11°C (52°F), whereas August features milder temperatures that range from a minimum of 4°C (39°F) to an average of 17°C (63°F). The maximum temperatures in September reach 26°C (79°F), slightly lower than August’s peak of 30°C (86°F). Additionally, September sees more rainfall, with 75 mm (2.9 in) over approximately 10 days, compared to August’s 88 mm (3.5 in) over 12 days, while humidity levels also rise in September to 84%, up from 73% in August. For a detailed look at August weather patterns, you can visit Irkutsk weather in August.
September and October bring notable changes in weather patterns. September sees a wider temperature range, with minimums around -1°C (31°F) and maximums reaching 26°C (79°F), averaging 11°C (52°F). This month also experiences higher precipitation, totaling 75 mm (2.9 in) over approximately 10 days. In contrast, October's climate cools significantly, with temperatures dipping to a minimum of -8°C (18°F) and an average of only 3°C (37°F), even as the maximums remain fairly mild at 22°C (71°F). Precipitation drops to 25 mm (1.0 in) over just 6 days, while the humidity remains constant at 84%. For more detailed information, you can check Irkutsk weather in October.
September and November present stark contrasts in weather conditions. In September, temperatures range from a chilly minimum of -1°C (31°F) to a pleasant maximum of 26°C (79°F), with an average of 11°C (52°F). The month sees about 75 mm (2.9 in) of precipitation spread over 10 days, and the humidity is relatively high at 84%. In contrast, November experiences much colder temperatures, with a minimum plunging to -28°C (-18°F), and an average of -7°C (20°F) alongside a maximum of 10°C (50°F). Precipitation significantly decreases to just 13 mm (0.5 in) over 4 days, while humidity remains higher at 90%. For a more detailed look at the weather in November, you can visit Irkutsk weather in November.
In September, the weather is considerably milder, with temperatures ranging from a minimum of -1°C (31°F) to an average of 11°C (52°F) and a maximum of 26°C (79°F). The month also sees about 75 mm (2.9 in) of precipitation over approximately 10 days, accompanied by a humidity level of 84%. In stark contrast, December brings frigid temperatures, with a minimum of -39°C (-38°F) and an average of -17°C (2°F), peaking at just 3°C (38°F). Precipitation drops significantly to 19 mm (0.7 in) over 5 days, and the humidity remains high at 96%. Overall, September offers a much warmer and wetter climate compared to the harsh and dry winter conditions of December. For more details, you can check out Irkutsk weather in December.
As September unfolds in Irkutsk, the weather begins to transition from the warmth of summer to the chill of autumn. This month experiences a noticeable drop in temperatures, with more unpredictable weather patterns leading to increased rainfall and higher humidity levels. While typical summer warmth fades, the lingering mild days provide a unique charm, contrasting sharply with the brisk chill that follows in October. September's weather is marked by a delicate balance, making it a perfect time for those looking to experience the stunning natural beauty of the region as it transitions into vibrant autumn hues. To learn more about what to expect throughout the year, visit Irkutsk Climate.