September Weather in Brno, Czech Republic

Last updated: April 1, 2025

September in Brno, Czech Republic offers a delightful transition from summer to autumn, characterized by a maximum temperature reaching up to 30°C (86°F) and an average of 15°C (59°F). Visitors can expect cooler nights with lows dipping to 0°C (31°F). The month experiences a total precipitation of 91 mm (3.6 in) over approximately 10 days, contributing to a humidity level of around 75%. This mix of warm days and crisp evenings sets the stage for a picturesque autumn, making it an ideal time for exploring the vibrant city and its surroundings.

September Temperature in Brno

As September unfolds in Brno, Czech Republic, the transition from the warmth of summer to the crispness of autumn begins to take shape. With temperatures ranging from a chilly 0°C (31°F) at night to a pleasant 30°C (86°F) during the day, this month offers a delightful mix of mild conditions. The average temperature hovers around 15°C (59°F), making September an ideal time for outdoor explorations. As the days gradually shorten, the warmth of late summer still lingers, inviting residents and visitors alike to savor the beauty of the changing season before the cooler months set in. It's a perfect blend of warmth and freshness that truly captures the charm of Brno in early fall.

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

The chart illustrates September temperature patterns in Brno, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec303440485666676859504134
Data source: Temperature data for Brno 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 Brno

September marks a notable increase in precipitation in Brno, Czech Republic, with 91 mm (3.6 in) of rain falling over an average of 10 days. This uptick contrasts with the drier summer months, where rainfall hovered around 70 mm and 12 days of precipitation were recorded. The transition into autumn is marked not just by the vibrant change in foliage but also by a significant surge in moisture, as September’s rainfall surpasses that of all preceding months. This trend indicates a shift towards the wetter months ahead, setting the stage for October and November, which typically see lower precipitation levels of 56 mm and 46 mm, respectively. As Brno moves deeper into fall, the changing weather patterns serve as a reminder of the dynamic climate experienced during this time of year.

September Precipitation Trends in Brno

The chart displays monthly precipitation patterns in Brno, 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.
JanFebMarAprMayJunJulAugSepOctNovDec333536368279807191564651
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Brno

As September rolls into Brno, the humidity begins to trend downwards from the summer peak, settling at a comfortable 75%. This slight decrease reflects a gradual transition from the warmer months, where humidity hovered around 76% in both July and August. In contrast, the winter months, particularly in January and February, see levels soar back up to 90% and 87%, respectively. The overall pattern indicates that Brno experiences its highest humidity at the start of the year, while September marks the start of a notable shift towards drier conditions, paving the way for the crisp, cooler air of autumn.

September Average Humidity in Brno

This chart illustrates the average monthly humidity levels in Brno, with September's data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, allowing you to see how September's humidity levels compare to other months.
JanFebMarAprMayJunJulAugSepOctNovDec90%87%85%78%74%77%76%76%75%85%90%91%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Brno

As September rolls into Brno, the UV Index settles at 6, classifying the exposure as high with a burn time of 25 minutes. This marks a gentle decline from the sweltering months of summer, where the Index peaked at 8 in both June and July. With the arrival of autumn, it's a reminder to still be cautious, especially for those enjoying outdoor activities. As temperatures start to drop and days shorten, the sun’s intensity remains significant, making it essential to stay vigilant against UV exposure. For more detailed insights, visit Brno UV Index.

Maximum UV Index Levels in Brno for September

The chart shows the monthly maximum UV Index (UVI) for Brno 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.
JanFebMarAprMayJunJulAugSepOctNovDec235688876422
Data source: Brno 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 Brno

As summer gracefully transitions into autumn, September in Brno showcases a delightful balance of sunshine, boasting 315 hours of bright skies. The month stands out as a reminder of the warm sunny days that linger after the height of summer, notably from July's peak of 433 hours. As daylight begins to wane with the approaching fall, September's hours still reflect a significant wealth of sunshine compared to the colder months ahead, such as October's 266 hours. This trend of gradually decreasing sunlight paints a vivid picture of the seasonal shift, allowing residents and visitors alike to relish the last warm moments before winter sets in.

Monthly Sunshine Duration in Brno: September Highlighted

The September sunshine duration represents the total number of hours Brno 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.
JanFebMarAprMayJunJulAugSepOctNovDec130h210h295h334h381h411h433h386h315h266h177h157h
Data source: Brno September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Brno During September

In Brno, Czech Republic, the likelihood of sunny weather in September stands at a noteworthy 46%, reflecting a trend of increasing sunlight as summer transitions into autumn. This sunshine probability is notably higher than the preceding months, especially when compared to the earlier summer peak of 47% in June and the decline in August, which saw only 34% sunny days. As the days grow shorter, September maintains an almost consistent chance of sunny weather similar to October, suggesting a pleasant and bright commencement to the fall season. This upward trend makes September an appealing time for outdoor activities, marking it as one of the more favorable months for basking in Brno’s natural beauty.

Percentage of Sunny Days in September in Brno

The chart illustrates the percentage of sunny days in Brno 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 Brno experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec22%31%50%36%35%47%43%34%46%46%23%17%
Data source: Brno September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Brno in September

As summer transitions into autumn, September in Brno, Czech Republic, captures the essence of changing daylight, offering approximately 12 hours of sunlight. This marks a gentle decline from the sun-soaked days of June, which boasts a generous 16 hours. The month of September provides a lovely balance, with longer days than the brisk months ahead, yet shorter than the peak of summer. Following its vibrant August with 14 hours of daylight, September serves as a reminder of the approaching fall, gradually leading us towards the shorter days of October, which will see daylight dwindle to 10 hours. The trend highlights a natural ebb and flow, with Brno's daylight illuminating the beauty of each season's transition.

Average Daylight Hours in Brno for September

The chart illustrates the variation in daylight duration in Brno throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec8h 41m10h 8m11h 55m13h 45m15h 20m16h 9m15h 43m14h 18m12h 32m10h 43m9h 5m8h 14m
Data source: Brno daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Brno

As September rolls into Brno, the wind begins to whisper a subtle transition, maintaining an average speed of 2.6 m/s (6 mph). This gentle breeze mirrors the calming trend observed during the summer months, hinting at a slower rhythm as the city prepares for autumn. While the winds were slightly stronger earlier in spring and early summer, September's gusts become softer, just as the colorful leaves start to blush against the clear skies. With autumn on the horizon, the atmosphere remains inviting, providing the perfect backdrop for leisurely strolls through the picturesque streets of Brno. The shift in wind speed not only reflects the changing seasons but also sets the tone for cozy gatherings and autumnal festivities that await the city.

Average September Wind Speed in Brno

The chart displays monthly wind speed patterns in Brno, 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.
JanFebMarAprMayJunJulAugSepOctNovDec3.03.12.93.63.72.52.82.62.6 m/s3.53.23.3
Data source: Brno September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Brno Compares to Other Months

The weather in Brno changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of September's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in Brno and find detailed weather information for every month.

September and January present stark contrasts in weather patterns. September experiences a range of temperatures with a minimum of 0°C (31°F) and a maximum of 30°C (86°F), leading to a pleasant average of 15°C (59°F). With higher humidity at 75% and 91 mm (3.6 in) of precipitation over about 10 days, it's a more transitional and mild time of year. In contrast, January is notably colder, with temperatures dropping to a minimum of -17°C (2°F) and an average of -1°C (31°F), peaking at 12°C (54°F). The month sees significantly less precipitation at 33 mm (1.3 in) across 9 days, but the humidity rises to 90%, contributing to the cold, crisp air. For a more detailed look at January weather, you can check Brno weather in January.

September and February present stark contrasts in weather. September typically sees warmer temperatures, with a minimum of 0°C (31°F) and an average of 15°C (59°F), peaking at 30°C (86°F). This month also experiences higher precipitation, averaging 91 mm (3.6 in) over about 10 days, and moderate humidity levels around 75%. In contrast, February is much colder, with temperatures ranging from a minimum of -15°C (4°F) to a maximum of 15°C (60°F) and an average of just 1°C (34°F). Precipitation in February is lower, averaging 35 mm (1.4 in) over 8 days, accompanied by a slightly higher humidity of 87%. For more details about February weather, you can visit Brno weather in February.

September and March present contrasting weather patterns. In September, temperatures range from a minimum of 0°C (31°F) to a pleasant maximum of 30°C (86°F), leading to an average of 15°C (59°F). The month sees approximately 91 mm (3.6 in) of precipitation over about 10 days, with relative humidity at 75%. In contrast, March is significantly cooler, with temperatures ranging from a low of -16°C (4°F) to a high of 21°C (69°F) and an average temperature of only 4°C (40°F). This month receives less precipitation, about 35 mm (1.4 in) over 7 days, but has higher humidity at 85%. For more details, you can check Brno weather in March.

In comparing the weather of September and April, one can observe notable differences in temperature and precipitation levels. September typically experiences a broader temperature range, with minimums around 0°C (31°F) and maximums reaching up to 30°C (86°F), resulting in an average temperature of 15°C (59°F). In contrast, April's temperatures are generally cooler, with a minimum of -6°C (21°F) and a maximum of 26°C (80°F), yielding an average of 9°C (49°F). Additionally, September tends to be wetter, accumulating 91 mm (3.6 inches) of precipitation over about 10 days, while April sees significantly less rainfall at 36 mm (1.4 inches) across 9 days. Despite both months exhibiting high humidity, September's 75% contrasts slightly with April's 78%. For a detailed look at April weather specifics, you can visit Brno weather in April.

September and May exhibit distinct weather patterns. In September, temperatures range from a minimum of 0°C (31°F) to a maximum of 30°C (86°F), with an average of 15°C (59°F). The month sees about 91 mm (3.6 in) of rainfall across 10 days, contributing to higher humidity levels at 75%. In contrast, May experiences slightly cooler conditions, with temperatures dipping to a minimum of -1°C (30°F) and peaking at 31°C (87°F), averaging 13°C (56°F). May has a bit less rainfall, with 82 mm (3.2 in) over 15 days, and a marginally lower humidity of 73%. For more details on the weather in May, check out Brno weather in May.

In comparing the weather of September and June, we see notable differences in temperature and precipitation. September experiences cooler temperatures, with a minimum of 0°C (31°F) and an average temperature of 15°C (59°F), while June starts off warmer, with a minimum of 6°C (43°F) and an average of 19°C (67°F). The maximum temperatures are also slightly higher in June, reaching up to 32°C (90°F) compared to September's peak of 30°C (86°F). Precipitation-wise, September sees a bit more rain, totaling 91 mm (3.6 in) over 10 days, while June has 79 mm (3.1 in) over 12 days. Humidity levels are relatively similar, with September at 75% and June a touch higher at 77%. For more detailed insights into June's weather, you can check Brno weather in June.

In comparing the weather of September and July, it's evident that July tends to be warmer overall. The average temperature in July reaches 20°C (67°F), with maximums peaking at 33°C (92°F), while September's average is cooler at 15°C (59°F) and can reach a maximum of 30°C (86°F). Precipitation levels are fairly similar, with July receiving 80 mm (3.1 in) over 12 days and September slightly higher at 91 mm (3.6 in) over 10 days. Both months exhibit high humidity, around 75% in September and slightly higher at 76% in July. For a more detailed look at July's climate, you can visit Brno weather in July.

In August, the temperatures were generally warmer, with a minimum of 7°C (45°F) and an average of 20°C (69°F), peaking at 34°C (93°F). This month also saw a bit less precipitation, totaling 71 mm (2.8 in) over 12 days, and the humidity remained high at 76%. In contrast, September experienced cooler temperatures, with a minimum of 0°C (31°F) and an average of 15°C (59°F), reaching a maximum of 30°C (86°F). Although September had higher precipitation levels at 91 mm (3.6 in) over 10 days, the humidity was slightly lower at 75%. For a more detailed overview, check out Brno weather in August.

September typically enjoys a warmer climate compared to October, with average temperatures around 15°C (59°F) and daytime highs peaking at 30°C (86°F). In contrast, October sees a notable drop in temperatures, averaging just 10°C (50°F), with maximums reaching 22°C (72°F) and a minimum dipping to -2°C (28°F). Although both months experience precipitation over ten days, September is wetter, receiving 91 mm (3.6 in) compared to October's 56 mm (2.2 in). Additionally, October's humidity is higher at 85%, creating a cooler, more damp atmosphere. For more information on October weather specifics in Brno, visit Brno weather in October.

September typically boasts a warmer climate, with temperatures ranging from a minimum of 0°C (31°F) to a maximum of 30°C (86°F) and an average of 15°C (59°F). The month sees about 91 mm (3.6 in) of precipitation over approximately 10 days, with humidity averaging 75%. In contrast, November brings colder weather, with temperatures dipping as low as -8°C (18°F) and averaging around 5°C (41°F), maxing out at 16°C (62°F). This month has lower precipitation of 46 mm (1.8 in) over about 9 days, but higher humidity at 90%. For a more detailed look at November weather, visit Brno weather in November.

September and December present contrasting weather patterns. In September, temperatures range from a minimum of 0°C (31°F) to a maximum of 30°C (86°F), with an average of 15°C (59°F). The month experiences 91 mm (3.6 in) of precipitation over about 10 days, accompanied by a relatively moderate humidity of 75%. In sharp contrast, December sees much colder temperatures, with a minimum of -7°C (20°F) and a maximum of only 10°C (51°F), resulting in an average temperature of just 1°C (34°F). Although December has less precipitation overall at 51 mm (2.0 in), it is spread over 13 days and comes with higher humidity at 91%. For more details on weather conditions, you can check Brno weather in December.

Compare Brno's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Brno

As summer gracefully transitions into autumn, September in Brno brings a delightful change in weather patterns, making it a unique month to experience. The warmth lingers with maximum temperatures reaching a comfortable 30°C (86°F), while the average cools down to a refreshing 15°C (59°F). This month also sees increased humidity levels around 75%, adding a certain richness to the air. Although 10 days of precipitation can make an appearance, it typically doesn't deter outdoor activities, as the rainfall amounts are usually manageable. Whether you're exploring the city's historical sites or enjoying its natural landscapes, September offers a beautiful blend of summer’s warmth and autumn's crispness, setting it apart from other months. For more in-depth details about the weather patterns, you can check out Brno Climate.