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September Weather in Hartford, United States

Last updated: June 24, 2025

In Hartford, United States, the average temperature in September hovers around 16°C (61°F). Expect a range that dips as low as -2°C (28°F) and can soar up to 31°C (88°F). This month sees about 61 mm (2.4 in) of precipitation spread over 8 days, accompanied by an average humidity of 71%. Perfect for those who enjoy a mix of mild weather and the occasional shower!

September Temperature in Hartford

In September in Hartford, the average temperature is 16°C (61°F). The maximum can reach 31°C (88°F), while the minimum can drop to as low as -2°C (28°F). Be prepared for a wide range of weather conditions when traveling during this month.

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 16°C (61°F), with highs reaching up to 31°C (88°F) and lows dropping to around -2°C (28°F).
JanFebMarAprMayJunJulAugSepOctNovDec202330435565706861493525
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 61 mm (2.4 in) distributed over 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 61 mm (2.4 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec717967113808812584611309996
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 71%. With an average temperature of 16°C (61°F), this humidity feels like walking through a warm, damp blanket, making travel slightly uncomfortable but still enjoyable for those who appreciate mild weather.

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 71%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%84%82%80%72%72%67%66%71%79%84%81%
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-6°C (21°F)70 mm (2.8 inches)86%moderate
February Weather-5°C (24°F)79 mm (3.1 inches)84%moderate
March Weather-1°C (31°F)67 mm (2.6 inches)82%high
April Weather6°C (43°F)113 mm (4.4 inches)80%very high
May Weather13°C (56°F)80 mm (3.2 inches)72%very high
June Weather18°C (65°F)88 mm (3.5 inches)72%very high
July Weather21°C (70°F)125 mm (4.9 inches)67%very high
August Weather20°C (68°F)84 mm (3.3 inches)66%very high
September Weather16°C (61°F)61 mm (2.4 inches)71%high
October Weather10°C (50°F)130 mm (5.1 inches)78%moderate
November Weather1°C (35°F)99 mm (3.9 inches)84%moderate
December Weather-4°C (25°F)96 mm (3.8 inches)81%low

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