September Weather in Olsztyn, Poland

Last updated: August 27, 2025

September in Olsztyn, Poland offers a delightful transition into autumn, featuring a maximum temperature of 30°C (87°F) and an average of 14°C (58°F). While the minimum temperature dips to 2°C (36°F), the month is characterized by a comfortable humidity level of 71%, creating a pleasant climate for outdoor activities. Rainfall totals around 73 mm (2.9 in), falling on about 11 days, ensuring the landscape remains lush and vibrant. Visitors can expect both warm days and cooler evenings, perfect for exploring the beauty of this charming city as summer gracefully gives way to fall.

September Temperature in Olsztyn

In September, Olsztyn begins to transition from the warmth of summer to the crispness of autumn. With minimum temperatures hovering around 2°C (36°F), residents and visitors can expect a pleasant shift in the weather, offering an average of 14°C (58°F), perfect for outdoor activities. As the days shorten, the maximum temperatures can still reach up to 30°C (87°F), reminding us that the tail end of summer isn't quite ready to bow out. This blend of cool mornings and warmer afternoons makes September a vibrant month, ideal for enjoying the colorful foliage and the region's natural beauty as it prepares for the cooler months ahead. The gradual decline in temperatures hints at the changes to come, creating a delightful contrast that captures the essence of early autumn in Poland.

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

The chart illustrates September temperature patterns in Olsztyn, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Olsztyn, 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).
JanFebMarAprMayJunJulAugSepOctNovDec303137455465656557494134
Data source: Temperature data for Olsztyn 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 Olsztyn

In September, Olsztyn experiences a notable consistency in its precipitation patterns, with rainfall reaching 73 mm (2.9 in) over 11 days. This volume is on par with August, indicating a gradual transition into the wetter autumn season. The steady precipitation suggests that the region is moving away from the drier summer months, yet it's a slight decrease compared to the peak July rainfall of 101 mm (4.0 in). As the month unfolds, the balance of rainy days paints a picture of a temperate climate, inviting the lush greenery characteristic of early autumn while maintaining a sense of the lingering warmth from summer.

September Precipitation Trends in Olsztyn

The chart displays monthly precipitation patterns in Olsztyn, 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 Olsztyn, September typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec4443463987601027373683851
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Olsztyn

In September, Olsztyn experiences a noticeable shift in humidity, with levels settling at 71%. This marks a transition from the drier summer months, as the city moves away from July's and August's more moderate humidity of 59% and 60%, respectively. Following the warmth of summer, the air begins to feel more saturated, hinting at the approach of autumn. The gradual increase to September’s humidity reflects the changing seasons, as the city braces for the wetter months ahead, culminating in a spike to 86% in October. As we progress toward the end of the year, Olsztyn residents can expect a return to the higher humidity levels characteristic of the winter months, reinforcing the cyclical nature of the local climate.

September Average Humidity in Olsztyn

This chart illustrates the average monthly humidity levels in Olsztyn, 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 Olsztyn is approximately {2}%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec92%90%87%76%58%56%59%60%71%86%90%93%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Olsztyn

As September rolls in, Olsztyn, Poland experiences a noticeable shift in UV exposure. With a UV Index of 5, categorized as moderate, residents and visitors alike are advised to take precautions similar to the earlier months of spring. Compared to the peak summer months where the index soared to 8, the decreased index signifies a welcome respite from potentially harmful rays, allowing for 30 minutes of sun exposure before burning occurs. This trend towards reduced UV levels is common as autumn approaches, offering a chance to enjoy the outdoors with relative safety in mind. However, as always, it’s wise to stay informed; for detailed UV forecasts, visit Olsztyn UV Index.

Maximum UV Index Levels in Olsztyn for September

The chart shows the monthly maximum UV Index (UVI) for Olsztyn 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 Olsztyn typically reaches {2}, which falls under the {3} exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec124568875321
Data source: Olsztyn 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 Olsztyn

As the summer wanes into autumn, September in Olsztyn offers a delightful transition, basking in approximately 300 hours of sunshine. This month continues the trend of warm, bright days established in the summer, with June peaking at 437 hours and July just slightly trailing with 426 hours. Although the sunshine starts to taper off as fall approaches, September maintains a robust share of sunlight compared to the darker months ahead, such as October's 235 hours and November's mere 147 hours. Embracing these radiant days is essential, as the sunshine gradually retreats, making September a vibrant and cherished moment in Olsztyn's climatic tapestry.

Monthly Sunshine Duration in Olsztyn: September Highlighted

The September sunshine duration represents the total number of hours Olsztyn 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.
JanFebMarAprMayJunJulAugSepOctNovDec93h178h255h343h402h437h426h383h300h235h147h120h
Data source: Olsztyn September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Olsztyn During September

In Olsztyn, Poland, the likelihood of enjoying sunny weather in September stands at 38%, which aligns closely with the trends observed during the late summer months. This rate maintains a similar level as seen in April and is notably higher than the dismal sun chances of January and November. However, it's less optimistic than the sun-soaked June, which boasts the highest likelihood at 57%. As the region transitions from the warmth of summer to the onset of autumn, September offers a pleasant mix of sunshine while hinting at the cooler, cloudier days that lie ahead. The gradual decline in sunny probabilities from the heights of summer suggests September is a sweet spot for enjoying the last rays of sun before fall fully sets in.

Percentage of Sunny Days in September in Olsztyn

The chart illustrates the percentage of sunny days in Olsztyn 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 Olsztyn experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec9%30%38%34%37%57%42%25%38%43%15%22%
Data source: Olsztyn September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Olsztyn in September

As summer fades, September in Olsztyn marks a gentle transition from the long, sunlit days of July and August, where daylight peaked at 16 hours. With 12 hours of daylight this month, there's a noticeable shift as autumn approaches. This decline, though moderate, foreshadows the shorter days ahead in October and November, where sunlight dwindles to 10 hours and ultimately 8 hours by the end of the year. The trend underscores a rhythm of light and dark, reminding us of nature’s cyclical dance as we prepare for the cooler, darker months ahead.

Average Daylight Hours in Olsztyn for September

The chart illustrates the variation in daylight duration in Olsztyn throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec8h 3m9h 47m11h 54m14h 3m15h 58m16h 58m16h 26m14h 43m12h 38m10h 29m8h 33m7h 30m
Data source: Olsztyn daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Olsztyn

As September arrives in Olsztyn, the wind begins to pick up slightly, averaging around 3.6 m/s (8 mph). This gradual increase from the calmer summer months, which saw winds around 2.8 to 3.4 m/s, indicates a shift in the season as nature gears up for autumn. Interestingly, while September's winds are relatively mild, they set the stage for October and November, where the average wind speed notably rises to 4.6 m/s (10 mph). Therefore, September serves as a transitional period—a gentle prelude to the brisk gusts awaiting in the fall months, inviting locals and visitors alike to enjoy the crisp air and changing leaves of Olsztyn.

Average September Wind Speed in Olsztyn

The chart displays monthly wind speed patterns in Olsztyn, 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.
JanFebMarAprMayJunJulAugSepOctNovDec3.83.93.93.84.02.82.93.43.6 m/s4.64.64.3
Data source: Olsztyn September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Olsztyn Compares to Other Months

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

The weather in September presents a mild warmth, with temperatures ranging from a minimum of 2°C (36°F) to a maximum of 30°C (87°F) and an average of 14°C (58°F). In contrast, January brings frigid temperatures, plummeting to a minimum of -21°C (-6°F) and peaking at 9°C (49°F), with an average of -1°C (31°F). While September sees more precipitation at 73 mm (2.9 in) over 11 days, January has a lower total of 44 mm (1.7 in) but experiences a higher humidity level of 92%. This stark contrast highlights the seasonal shift in weather as one moves from the warmth of late summer to the depths of winter. For more detailed information, you can check Olsztyn weather in January.

September and February present striking contrasts in weather. In September, temperatures range from a mild 2°C (36°F) at night to a warm 30°C (87°F) during the day, with an average of 14°C (58°F). The month experiences some precipitation, totaling 73 mm (2.9 in) over approximately 11 days, accompanied by a relative humidity of 71%. In stark contrast, February boasts much colder conditions, with minimum temperatures plummeting to -20°C (-4°F) and an average of 0°C (32°F), peaking at 14°C (58°F). Precipitation is lower in February at 43 mm (1.7 in) over 8 days, but the humidity is notably higher at 90%. For a detailed look at February weather, you can visit Olsztyn weather in February.

In comparing the weather between September and March, a notable contrast emerges. September boasts a more temperate climate with average temperatures around 14°C (58°F), peaking at a warm 30°C (87°F), and features relatively high humidity levels at 71%. This month also experiences moderate rainfall, totaling 73 mm (2.9 in) over 11 days. In contrast, March presents a much colder landscape, with average temperatures hovering around 3°C (37°F) and lows dipping as low as -16°C (3°F). While precipitation is less frequent at 46 mm (1.8 in) over the same number of rainy days, the humidity rises to 87%, contributing to a chilly atmosphere. For those interested in specific weather conditions, more details can be found at Olsztyn weather in March.

When comparing the weather in September and April, a notable difference in temperatures and precipitation patterns emerges. September experiences a milder climate with average temperatures ranging from 14°C (58°F) to a maximum of 30°C (87°F), while April is generally cooler, with an average of 7°C (46°F) and a minimum of -5°C (24°F). Precipitation in September totals 73 mm (2.9 in) over 11 days, compared to April's 39 mm (1.5 in) over just 9 days, indicating a wetter month at the onset of autumn. Moreover, September's humidity at 71% is slightly lower than April's at 76%, contributing to a more comfortable environment during the latter part of the year. For more detailed insights on April weather, visit Olsztyn weather in April.

When comparing the weather in September and May, one can observe distinct differences. September tends to have a wider temperature range, with minimums around 2°C (36°F) and maximums reaching up to 30°C (87°F), averaging at 14°C (58°F). In contrast, May starts off colder with a minimum temperature of -2°C (28°F) and has a slightly lower maximum of 28°C (83°F), resulting in an average temperature of 12°C (55°F). Additionally, September experiences less precipitation at 73 mm (2.9 in) over 11 days, while May sees a bit more rain at 87 mm (3.4 in) spread across 14 days. Humidity levels are higher in September at 71%, compared to May’s 58%. For more detailed insights on May weather in Olsztyn, you can visit Olsztyn weather in May.

September and June showcase distinct weather patterns, with June generally warmer and more humid. In June, temperatures range from a minimum of 3°C (37°F) to a maximum of 33°C (91°F), averaging around 18°C (65°F), while September sees cooler temperatures with a minimum of 2°C (36°F) and a maximum of 30°C (87°F), averaging 14°C (58°F). Additionally, September experiences slightly higher precipitation at 73 mm (2.9 in) compared to June's 59 mm (2.3 in), though both months have around 11 rainy days. Furthermore, June has lower humidity at 56%, contrasting with September's higher humidity level of 71%. For more details, you can check Olsztyn weather in June.

In comparing the weather patterns of September and July, we observe notable differences in temperature and precipitation. September experiences a broader range of temperatures, with minimums dropping to 2°C (36°F) and maximums reaching up to 30°C (87°F), resulting in an average of 14°C (58°F). In contrast, July maintains a milder minimum of 8°C (46°F) and a higher average temperature of 19°C (66°F), peaking at 32°C (90°F). Additionally, July sees more precipitation, totaling 101 mm (4.0 in) over 15 days, while September receives 73 mm (2.9 in) across 11 days, albeit with higher humidity levels at 71% compared to July's 59%. For further details, you can check Olsztyn weather in July.

In comparing the weather of September to that of August, September experiences a broader temperature range, with minimums as low as 2°C (36°F) and maximums reaching up to 30°C (87°F), while August stays warmer overall, with minimums at 8°C (47°F) and maximums peaking at 32°C (90°F). Precipitation levels remain consistent in both months at 73 mm (2.9 in), but September sees slightly more rainy days, totaling 11 compared to August's 12 days. Additionally, September's humidity is notably higher at 71%, compared to August's 60%. For more specific insights about August weather, you can explore Olsztyn weather in August.

September showcases a wider temperature range with lows of 2°C (36°F) and highs reaching up to 30°C (87°F), giving it a warm average of 14°C (58°F). The month experiences moderate rainfall, totaling 73 mm (2.9 in) across about 11 days, and maintains a humidity level of 71%.

In contrast, October marks a shift towards cooler weather, with temperatures dipping as low as -2°C (29°F) and an average of 10°C (50°F). The maximum temperature in October is notably lower at 22°C (71°F), while precipitation remains similar at 68 mm (2.7 in) but spreads across 12 days. The humidity also rises to 86%, making October feel considerably more damp and chilly in comparison. For more detailed insights, you can check out Olsztyn weather in October.

September weather is characterized by a wide temperature range, with minimums dipping to 2°C (36°F) and maximums reaching up to 30°C (87°F), resulting in an average temperature of 14°C (58°F). This month also experiences moderate precipitation, totaling 73 mm (2.9 in) over about 11 days, and a humidity level of 71%.

In contrast, November sees a significant drop in temperatures, with minimums falling to -6°C (22°F) and an average of only 5°C (41°F). The maximum temperature is much milder at 16°C (60°F). Precipitation decreases to 38 mm (1.5 in) over 10 days, and humidity levels rise to 90%, creating a much chillier and damp atmosphere. For more details on November weather conditions, you can explore Olsztyn weather in November.

In September, the weather features a broader temperature range with a minimum of 2°C (36°F) and a maximum of 30°C (87°F), making it generally warmer with an average of 14°C (58°F). Humidity is moderate at 71%, and the month experiences about 73 mm (2.9 in) of precipitation over 11 days. In contrast, December brings a significant drop in temperatures, with a chilly minimum of -12°C (10°F) and an average of just 1°C (34°F), peaking at 10°C (50°F). Despite slightly lower precipitation at 51 mm (2.0 in) over 12 days, the humidity rises sharply to 93%, contributing to a cold, damp atmosphere. For more information, you can check out Olsztyn weather in December.

Compare Olsztyn's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Olsztyn

As September unfolds in Olsztyn, the weather begins to transition from the warmth of summer to the cooler touch of autumn. While temperatures can still peak at a pleasant 30°C, the average dips to a comfortable 14°C, signaling a shift in the season. The month also experiences a fair amount of precipitation, with rain gracing 11 days, contributing to a 71% humidity level that adds a refreshing, crisp feeling to the air. This blend of warmth and moisture makes September distinctively vibrant compared to the drier, hotter months of summer. For a deeper insight into how Olsztyn's weather trends throughout the year, explore more at Olsztyn Climate.