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September Weather in Sliven, Bulgaria

Last updated: August 22, 2025

In September, the average temperature in Sliven, Bulgaria is a pleasant 18°C (65°F). While you may enjoy warm days with a maximum of 32°C (90°F), be prepared for cooler nights that can dip to a chilly 3°C (37°F). Throughout the month, expect a total precipitation of 29 mm (1.2 in) over about 5 days, contributing to an average humidity level of 58%.

September Temperature in Sliven

In September in Sliven, the average temperature is 18°C (65°F). Maximum temperatures can reach up to 32°C (90°F), while the minimum can drop as low as 3°C (37°F). This varying climate makes it essential for travelers to pack for both warm and cool conditions.

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

The chart illustrates September temperature patterns in Sliven, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Sliven, September typically has an average temperature of 18°C (65°F), with highs reaching up to 32°C (90°F) and lows dropping to around 3°C (37°F).
JanFebMarAprMayJunJulAugSepOctNovDec333842506067717365554638
Data source: Temperature data for Sliven 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 Sliven

In Sliven in September, the precipitation amount is 29 mm (1.2 in) over a period of 5 days.

September Precipitation Trends in Sliven

The chart displays monthly precipitation patterns in Sliven, 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 Sliven, September typically receives around 29 mm (1.2 inches) of precipitation spread over approximately 5 days.
JanFebMarAprMayJunJulAugSepOctNovDec5456755891150823629705989
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Sliven

In Sliven in September humidity is 58%. With an average temperature of 18°C (65°F), this humidity feels like a warm embrace, creating a comfortable yet slightly muggy atmosphere perfect for leisurely exploration.

September Average Humidity in Sliven

This chart illustrates the average monthly humidity levels in Sliven, 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 Sliven is approximately 58%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%84%81%70%72%66%62%48%58%78%85%87%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Sliven

In Sliven in September, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in Sliven.

Maximum UV Index Levels in Sliven for September

The chart shows the monthly maximum UV Index (UVI) for Sliven 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 Sliven typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec2468910997632
Data source: Sliven 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.

How September Weather in Sliven Compares to Other Months

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

This table compares monthly weather conditions in Sliven, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather0°C (33°F)54 mm (2.1 inches)88%low
February Weather3°C (38°F)55 mm (2.2 inches)84%moderate
March Weather5°C (42°F)75 mm (2.9 inches)81%high
April Weather10°C (50°F)58 mm (2.3 inches)70%very high
May Weather15°C (60°F)91 mm (3.6 inches)72%very high
June Weather19°C (67°F)150 mm (5.9 inches)66%very high
July Weather22°C (72°F)82 mm (3.2 inches)62%very high
August Weather23°C (73°F)36 mm (1.4 inches)48%very high
September Weather18°C (65°F)29 mm (1.2 inches)58%high
October Weather13°C (55°F)70 mm (2.7 inches)78%high
November Weather8°C (46°F)59 mm (2.3 inches)85%moderate
December Weather3°C (38°F)89 mm (3.5 inches)87%low

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