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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 20°C (69°F). It can range from a chilly 5°C (42°F) to a warm 33°C (92°F). Expect approximately 118 mm (4.6 in) of precipitation spread over 9 days, contributing to an average humidity of 73%. 🌦️

September Temperature in Hartford

In September in Hartford, the average temperature is 20°C (69°F). Maximum temperatures can reach 33°C (92°F), while minimums can drop as low as 5°C (42°F). Overall, it's a great time for travelers to enjoy a mix of warm days and cooler evenings in Hartford.

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 20°C (69°F), with highs reaching up to 33°C (92°F) and lows dropping to around 5°C (42°F).
JanFebMarAprMayJunJulAugSepOctNovDec232440506375777469533931
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 118 mm (4.6 in) over the course of 9 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 118 mm (4.6 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec4041837316612569761181314237
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 73%. With an average temperature of 20°C (69°F), this humidity feels like a warm embrace, making travel slightly sticky but ultimately comfortable as long as you stay hydrated and take breaks in the shade.

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 73%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec78%80%77%78%77%81%81%77%73%75%85%83%
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 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 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 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec35689111098643
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-5°C (23°F)40 mm (1.6 inches)78%moderate
February Weather-4°C (24°F)41 mm (1.6 inches)80%moderate
March Weather4°C (40°F)83 mm (3.3 inches)77%high
April Weather10°C (50°F)73 mm (2.9 inches)77%very high
May Weather17°C (63°F)166 mm (6.5 inches)77%very high
June Weather24°C (75°F)125 mm (4.9 inches)81%extreme
July Weather25°C (78°F)69 mm (2.7 inches)81%very high
August Weather24°C (75°F)76 mm (3.0 inches)77%very high
September Weather20°C (69°F)118 mm (4.6 inches)73%very high
October Weather12°C (53°F)131 mm (5.2 inches)75%high
November Weather4°C (39°F)42 mm (1.6 inches)85%moderate
December Weather0°C (31°F)37 mm (1.4 inches)83%moderate

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