September Weather in Olsztyn, Poland

Last updated: August 27, 2025

September in Olsztyn, Poland, showcases a dynamic range of weather, with temperatures fluctuating from a minimum of 1°C (34°F) to a maximum of 32°C (90°F), offering a true taste of early autumn. The average temperature settles at a mild 15°C (59°F), providing a comfortable backdrop for outdoor activities. This month also witnesses 87 mm (3.4 in) of precipitation over 11 days, contributing to the region's lush landscapes. With an average humidity of 72%, the air feels refreshingly crisp yet slightly damp, characteristic of this transitional season. Whether basking in the warmth of sunny afternoons or enjoying cooler evenings, September in Olsztyn is a time of stunning contrasts and vibrant natural beauty.

September Temperature in Olsztyn

In September, Olsztyn begins to transition from the warmth of summer towards the chill of autumn, with temperatures showcasing this shift. The month greets visitors with a minimum temperature of 1°C (34°F), climbing to a comfortable average of 15°C (59°F), and can surge to a maximum of 32°C (90°F) on warmer days. This broad range not only reflects the lingering summer warmth but also hints at the impending cooler months. As the days gradually shorten, early September often still enjoys the remnants of summer heat, while at night, the air turns crisp, making it a delightful time to explore the picturesque landscapes of the region. This blend of warm days and cool nights creates a unique charm that encourages both outdoor activities and cozy evenings.

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).
JanFebMarAprMayJunJulAugSepOctNovDec303439485667676859514235
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

As September rolls in Olsztyn, Poland, the precipitation levels reflect the transition from the warmer summer months to the crispness of autumn. With 87 mm (3.4 in) of rain, September marks a slight decrease from the 91 mm (3.6 in) recorded in August, yet remains high compared to earlier months, emphasizing the tail end of the summer rainfall pattern. Rainfall occurs over approximately 11 days, maintaining a steady rhythm similar to the previous month. This trend indicates that while the frequency of rain is somewhat consistent, the amounts are beginning to taper off as the region prepares for the dryer, chillier October. Overall, September’s weather serves as a bridge, gracefully balancing the lush summer excess with the incoming autumnal dryness.

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.
JanFebMarAprMayJunJulAugSepOctNovDec405042588376839187654056
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Olsztyn

As September arrives in Olsztyn, Poland, humidity levels start to shift from the dry warmth of summer, settling at a moderate 72%. This slight increase marks a transition from the 66-67% humidity experienced in the preceding months, hinting at the impending change of seasons. Following the drier days of late spring and summer, this uptick suggests a return to the dampness that characterizes the autumn months, as the region braces itself for the approaching chill. Indeed, the months that follow will see a notable rise, with October's humidity climbing to 83% and peaking again in winter, demonstrating a cyclical pattern where the warmth of summer gives way to the lush, moisture-laden air of fall and winter.

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.
JanFebMarAprMayJunJulAugSepOctNovDec90%88%86%79%65%66%67%67%72%83%90%92%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Olsztyn

As September rolls into Olsztyn, the UV Index registers a notable 6, indicating a high exposure category. This marks a slight decrease from the peak of summer, where the Index reached 8 in both July and June, demanding only 15 minutes of burn time. In contrast, September allows for a more generous 25 minutes before the risk of harm increases, highlighting a transitional phase as autumn approaches. This trend shows that while the bright summer sun begins to wane, it still poses a significant UV risk, reminding residents to stay vigilant about sun protection. For more insights into UV trends throughout the year, check out the full details at 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.
JanFebMarAprMayJunJulAugSepOctNovDec224578876321
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

September in Olsztyn, Poland, continues the delightful trend of abundant sunshine that peaks in the summer months. With an impressive 297 hours of sunshine, September gracefully transitions from the vibrant summer days of July and August, which boast 415 and 379 hours respectively. This month not only retains a significant amount of sunlight but also hints at the changing seasons ahead, offering a beautiful blend of warmth and the onset of autumn. As days shorten and cooler breezes begin to sweep in, the sunlight serves as a gentle reminder of the summer's lingering embrace, making September a truly enchanting time to experience Olsztyn's natural beauty.

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.
JanFebMarAprMayJunJulAugSepOctNovDec122h188h270h318h362h405h415h379h297h251h188h132h
Data source: Olsztyn September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Olsztyn During September

As summer transitions into autumn in Olsztyn, Poland, September presents a notable 38% chance of sunny weather. This reflects a slight increase from the peak summer months, particularly June, which boasts a robust 51% chance. While September's likelihood of sunshine is higher than the preceding months of August and July, it still trails behind the sunny promise of May and June, indicating that locals can expect pleasant, albeit gradually cooling, days. As the sun begins to play hide-and-seek with clouds later in the year, the trend shows a gradual decline into the autumn months, with October having a surprisingly optimistic 48% chance of sunshine.

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.
JanFebMarAprMayJunJulAugSepOctNovDec18%28%35%36%37%51%36%29%38%48%26%16%
Data source: Olsztyn September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Olsztyn in September

In September, Olsztyn experiences a transition towards the shorter days of autumn, with daylight lasting approximately 12 hours. This marks a gradual decline from the vibrant 16 hours of sunlight in June, followed by a steady decrease through the summer months. While August still offers a generous 14 hours, September heralds a noticeable shift as the days begin to shorten more rapidly, leading into October with its mere 10 hours of daylight. This pattern underscores a comforting yet inevitable cycle, as Olsztyn bids farewell to the long, sunlit days of summer and embraces the cozy embrace of autumn's early evenings.

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 29m10h 1m11h 54m13h 51m15h 32m16h 25m15h 57m14h 26m12h 34m10h 39m8h 55m8h
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 gentle breezes tend to linger, with an average wind speed of 3.4 m/s (8 mph). This transitional month sees a slight increase from the summer months, which often feature calmer winds of 2.8 m/s in July and June. September’s winds act as a prelude to the brisker conditions of autumn, hinting at the cooler days ahead while still offering a hint of warmth from the lingering summer. Following this month, October and November show a noticeable rise in wind speed, reaching up to 4.2 m/s, suggesting that Olsztyn's winds are set to pick up momentum as the seasons change. Overall, September strikes a delicate balance, making it a perfect time to enjoy the last whispers of summer alongside the invigorating onset of autumn.

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.
JanFebMarAprMayJunJulAugSepOctNovDec3.84.33.73.94.12.82.83.23.4 m/s4.24.14.1
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.

In September, the weather is notably warmer with temperatures ranging from a chilly minimum of 1°C (34°F) to a comfortable maximum of 32°C (90°F), averaging around 15°C (59°F). With average precipitation of 87 mm (3.4 in) over 11 days, the month also has a moderate humidity level at 72%. In contrast, January experiences much colder conditions, where temperatures drop significantly, with a minimum of -26°C (-15°F) and a maximum of 11°C (52°F), yielding an average of -1°C (31°F). Precipitation during this month is lower, at 40 mm (1.6 in) across 10 days, accompanied by higher humidity at 90%. For more details, refer to Olsztyn weather in January.

September and February present strikingly different weather patterns. In September, temperatures range from a chilly 1°C (34°F) at night to a warm 32°C (90°F) during the day, offering an average temperature of 15°C (59°F). The month sees around 87 mm (3.4 in) of precipitation over 11 days, accompanied by a humidity level of 72%. In contrast, February is considerably colder, with temperatures often dipping as low as -14°C (7°F) and peaking at 18°C (65°F), averaging just 1°C (34°F). Precipitation during February amounts to 50 mm (2.0 in), also spread over 11 days, but with an increased humidity of 88%. This comparison highlights the transition from the warmer, humid days of late summer to the chilly, damp conditions of winter, as detailed on Olsztyn weather in February.

September and March present contrasting weather patterns. In September, temperatures range from a chilly 1°C (34°F) to a warm 32°C (90°F), with an average of 15°C (59°F). The month is relatively humid at 72% and experiences 87 mm (3.4 in) of precipitation over 11 days. Conversely, March is significantly colder, with temperatures dipping as low as -15°C (5°F) and peaking at 21°C (70°F), averaging around 4°C (39°F). This month sees less precipitation at 42 mm (1.7 in), but it maintains a higher humidity level of 86%. For more details on March weather, check out Olsztyn weather in March.

When comparing the weather in September and April, noticeable differences emerge. September typically experiences a wider temperature range, with minimums around 1°C (34°F) and maximums reaching up to 32°C (90°F), resulting in an average temperature of 15°C (59°F). In contrast, April has cooler conditions, with minimums dropping to -7°C (20°F) and average temperatures around 9°C (48°F), while maximums can still reach 27°C (81°F). Precipitation levels are higher in September, totaling 87 mm (3.4 in) over 11 days, compared to April's 58 mm (2.3 in) over 10 days. The humidity is also slightly lower in September at 72%, versus April's higher average of 79%. For a more detailed look at April's weather in Olsztyn, check out Olsztyn weather in April.

In comparing the weather between September and May, September tends to offer a broader temperature range with minimums reaching 1°C (34°F) and maximums climbing up to 32°C (90°F). The average temperature is slightly higher at 15°C (59°F) compared to May's average of 14°C (57°F). Both months experience comparable precipitation levels, though September has slightly more at 87 mm (3.4 in) over 11 days, while May sees 83 mm (3.3 in) spread over 15 days. Additionally, May has a lower humidity level at 65% compared to September's 72%, contributing to the distinct seasonal feel of each month. For more specific details about May’s weather, check out Olsztyn weather in May.

In comparing the weather of September and June, we can see distinct differences in both temperature and precipitation patterns. September experiences a broader range of temperatures, with a minimum of 1°C (34°F) and a maximum of 32°C (90°F), resulting in an average temperature of 15°C (59°F). In contrast, June boasts warmer conditions, beginning with a minimum temperature of 5°C (42°F) and peaking at 35°C (95°F), yielding an average of 19°C (67°F). While September has a higher average precipitation of 87 mm (3.4 in) over 11 days, June's rainfall totals 76 mm (3.0 in) across 12 days. Additionally, humidity levels are slightly higher in September at 72%, compared to June’s 66%. For more details on June weather, you can refer to Olsztyn weather in June.

When comparing the weather in September to that of July, we observe some distinct differences. September features a wider temperature range, with a minimum of 1°C (34°F) and a maximum of 32°C (90°F), while July is generally warmer, with a minimum of 8°C (46°F) and a maximum of 37°C (99°F). The average temperature in September is a comfortable 15°C (59°F), which is lower than July's more balmy average of 20°C (68°F). Precipitation levels are fairly similar, with September receiving 87 mm (3.4 in) over 11 days and July slightly less at 83 mm (3.3 in) over 13 days. The humidity is also slightly higher in September at 72%, compared to July's 67%. For more details on July's weather, check out Olsztyn weather in July.

In comparing the weather between September and August, September displays a notable decrease in average temperatures, with minimums dropping to 1°C (34°F) compared to August's 7°C (44°F). While September can still reach a maximum of 32°C (90°F), the average temperature is lower at 15°C (59°F) than the 20°C (68°F) average seen in August. Precipitation levels are fairly similar, with September receiving 87 mm (3.4 in) over 11 days and August seeing slightly more at 91 mm (3.6 in) over 12 days. Additionally, September's humidity is higher at 72%, compared to August's 67%. For more detailed information, check out Olsztyn weather in August.

September weather is characterized by a significant temperature range, with minimums reaching 1°C (34°F) and maximums soaring up to 32°C (90°F), resulting in an average temperature of 15°C (59°F). The month sees a fair amount of precipitation, totaling 87 mm (3.4 in) over 11 days, accompanied by a humidity level of 72%. In contrast, October experiences a cooler climate, with temperatures dropping to a minimum of -3°C (27°F) and peaking at 24°C (76°F), leading to a lower average of 11°C (51°F). Although precipitation decreases to 65 mm (2.6 in) over the same number of days, humidity rises to 83%. For those interested in more detailed weather patterns, check out Olsztyn weather in October.

September and November present stark contrasts in weather patterns. In September, temperatures range from a minimum of 1°C (34°F) to a maximum of 32°C (90°F), with an average of 15°C (59°F) and relatively limited precipitation of 87 mm (3.4 in) over 11 days. In contrast, November's climate is much cooler, experiencing a minimum of -7°C (19°F) and a maximum of 19°C (67°F), averaging just 6°C (42°F). Additionally, November sees less precipitation at 40 mm (1.6 in) over 9 days but has higher humidity at 90%. For a more detailed insight into November’s weather, check out Olsztyn weather in November.

September and December showcase stark contrasts in weather. In September, temperatures range from a mild 1°C (34°F) at night to a warm 32°C (90°F) during the day, with an average of 15°C (59°F). The month sees about 87 mm (3.4 in) of precipitation spread over 11 days, accompanied by a relatively comfortable humidity of 72%. In contrast, December brings chilling conditions, with nighttime temperatures dropping to a frigid -14°C (7°F) and daytime highs peaking at 14°C (58°F), averaging just 1°C (35°F). The precipitation is lighter at 56 mm (2.2 in), though it occurs over 13 days, and humidity rises significantly to 92%. For a more detailed look at December's climate, you can check 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 presents a delightful transition from the warmth of summer to the cooling embrace of autumn. Average temperatures hover around a mild 15°C, providing a comfortable respite from the high summer peaks. While maximum temperatures can still soar up to 32°C, the arrival of cooler nights signals the season's shift, with lows diving to 1°C. Precipitation, accumulating over about 11 days, contributes to the region’s 72% humidity, creating a refreshing yet occasionally damp atmosphere. This blend of warmth and moisture makes September a captivating month, distinct from the extremes often seen in July and August. For a deeper understanding of what to expect throughout the year, explore the detailed insights available at Olsztyn Climate.