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September Weather in Southbury, United States

Last updated: June 24, 2025

In Southbury, United States, the average temperature in September hovers around 19°C (67°F). Expect minimums to dip to 4°C (40°F) and maximums to soar up to 33°C (92°F). This month, prepare for about 114 mm (4.5 in) of precipitation spread over 9 days. With an average humidity of 68%, it's a time to embrace the mix of warmth and refreshing rain!

September Temperature in Southbury

In September in Southbury, the average temperature is 19°C (67°F). Maximums can reach 33°C (92°F) while minimums can be as low as 4°C (40°F). This range makes it an ideal time for travelers to enjoy a variety of outdoor activities while also being prepared for cooler evenings.

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

The chart illustrates September temperature patterns in Southbury, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Southbury, September typically has an average temperature of 19°C (67°F), with highs reaching up to 33°C (92°F) and lows dropping to around 4°C (40°F).
JanFebMarAprMayJunJulAugSepOctNovDec303338495969747366564335
Data source: Temperature data for Southbury 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 Southbury

In Southbury in September, the precipitation amount is 114 mm (4.5 in) over the course of 9 days.

September Precipitation Trends in Southbury

The chart displays monthly precipitation patterns in Southbury, 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 Southbury, September typically receives around 114 mm (4.5 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec71969112911210314310611414394121
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Southbury

In Southbury in September, humidity is 68%. With an average temperature of 19°C (67°F), this humidity feels like a warm, enveloping blanket, making travel pleasant yet slightly muggy, which can be refreshing while exploring but may require occasional breaks to stay comfortable.

September Average Humidity in Southbury

This chart illustrates the average monthly humidity levels in Southbury, 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 Southbury is approximately 68%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%82%81%78%70%69%62%65%68%74%82%80%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Southbury

In Southbury in September, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in Southbury.

Maximum UV Index Levels in Southbury for September

The chart shows the monthly maximum UV Index (UVI) for Southbury 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 Southbury typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec356810101098642
Data source: Southbury 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 Southbury Compares to Other Months

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

This table compares monthly weather conditions in Southbury, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-1°C (31°F)71 mm (2.8 inches)84%moderate
February Weather1°C (33°F)96 mm (3.8 inches)82%moderate
March Weather4°C (39°F)91 mm (3.6 inches)81%high
April Weather9°C (49°F)129 mm (5.1 inches)78%very high
May Weather15°C (59°F)112 mm (4.4 inches)69%very high
June Weather20°C (69°F)102 mm (4.0 inches)69%very high
July Weather24°C (75°F)143 mm (5.6 inches)62%very high
August Weather23°C (73°F)106 mm (4.2 inches)65%very high
September Weather19°C (67°F)114 mm (4.5 inches)68%very high
October Weather14°C (57°F)143 mm (5.6 inches)74%high
November Weather6°C (43°F)94 mm (3.7 inches)82%moderate
December Weather1°C (35°F)121 mm (4.8 inches)80%low

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