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September Weather in Hartford, United States

Last updated: June 24, 2025

In September, the average temperature in Hartford, United States is a pleasant 18°C (64°F). Expect a minimum of 1°C (33°F) and a maximum reaching up to 33°C (92°F). During this time, you'll likely see about 76 mm (3.0 in) of precipitation spread across 8 days, with an average humidity of 72%. Stay prepared for a mix of weather!

September Temperature in Hartford

In September in Hartford, the average temperature is 18°C (64°F). The maximum can reach 33°C (92°F), and the minimum can be as low as 1°C (33°F). Be prepared for a wide range of weather conditions when traveling to Hartford during this time.

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

The chart illustrates September temperature patterns in Hartford, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Hartford, September typically has an average temperature of 18°C (64°F), with highs reaching up to 33°C (92°F) and lows dropping to around 1°C (33°F).
JanFebMarAprMayJunJulAugSepOctNovDec252734465967737164533830
Data source: Temperature data for Hartford 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 Hartford

In Hartford in September, the precipitation amount is 76 mm (3.0 in) spread over a duration of 8 days.

September Precipitation Trends in Hartford

The chart displays monthly precipitation patterns in Hartford, 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 Hartford, September typically receives around 76 mm (3.0 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec7891721198583114847614110495
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Hartford

In Hartford in September, humidity is 72%. With an average temperature of 18°C (64°F), this humidity feels like a warm, sticky embrace, making travel somewhat uncomfortable as the air clings to your skin, leaving you longing for a refreshing breeze.

September Average Humidity in Hartford

This chart illustrates the average monthly humidity levels in Hartford, 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 Hartford is approximately 72%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec90%88%86%84%76%72%67%64%72%81%87%85%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Hartford

In Hartford 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 Hartford.

Maximum UV Index Levels in Hartford for September

The chart shows the monthly maximum UV Index (UVI) for Hartford 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 Hartford typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3468910997532
Data source: Hartford 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 Hartford Compares to Other Months

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

This table compares monthly weather conditions in Hartford, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-4°C (25°F)78 mm (3.1 inches)89%moderate
February Weather-3°C (27°F)91 mm (3.6 inches)88%moderate
March Weather1°C (34°F)72 mm (2.9 inches)86%high
April Weather8°C (47°F)119 mm (4.7 inches)84%very high
May Weather15°C (59°F)85 mm (3.3 inches)76%very high
June Weather20°C (68°F)83 mm (3.3 inches)72%very high
July Weather23°C (73°F)114 mm (4.5 inches)66%very high
August Weather22°C (71°F)84 mm (3.3 inches)64%very high
September Weather18°C (64°F)76 mm (3.0 inches)72%high
October Weather11°C (53°F)141 mm (5.6 inches)81%moderate
November Weather3°C (38°F)104 mm (4.1 inches)87%moderate
December Weather-1°C (30°F)94 mm (3.7 inches)84%low

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