nomadseason

September Weather in Hartford, United States

Last updated: June 24, 2025

In September, the average temperature in Hartford, United States is a comfortable 20°C (67°F). However, be prepared for fluctuations, as temperatures can dip to a minimum of 6°C (43°F) and reach as high as 32°C (90°F). The region experiences about 75 mm (3.0 in) of precipitation over 9 days, contributing to a relatively high average humidity of 79%.

September Temperature in Hartford

In September in Hartford, the average temperature is 20°C (67°F). Maximums can reach 32°C (90°F), while minimums can drop to as low as 6°C (43°F). This variation in temperature makes it essential for travelers to pack appropriately for both warm and cool conditions.

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 (67°F), with highs reaching up to 32°C (90°F) and lows dropping to around 6°C (43°F).
JanFebMarAprMayJunJulAugSepOctNovDec282837465870757367554135
Data source: Temperature data for Hartford generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
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 75 mm (3.0 in) distributed over 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 75 mm (3.0 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec74737910215113310678751467267
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in Hartford

In Hartford in September, humidity is 79%. With an average temperature of 20°C (67°F), this humidity feels like a warm, heavy blanket wrapping around you, making traveling a bit sluggish and requiring frequent breaks to stay refreshed.

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 79%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec87%87%86%87%82%81%78%79%80%82%87%86%
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.
JanFebMarAprMayJunJulAugSepOctNovDec24589101097532
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-2°C (28°F)74 mm (2.9 inches)87%low
February Weather-2°C (29°F)73 mm (2.9 inches)87%moderate
March Weather3°C (37°F)79 mm (3.1 inches)86%moderate
April Weather8°C (46°F)102 mm (4.0 inches)87%very high
May Weather14°C (58°F)151 mm (5.9 inches)82%very high
June Weather21°C (70°F)133 mm (5.3 inches)81%very high
July Weather24°C (75°F)106 mm (4.2 inches)78%very high
August Weather23°C (73°F)78 mm (3.1 inches)79%very high
September Weather20°C (67°F)75 mm (3.0 inches)79%high
October Weather13°C (56°F)146 mm (5.7 inches)82%moderate
November Weather5°C (42°F)72 mm (2.8 inches)87%moderate
December Weather2°C (35°F)67 mm (2.6 inches)86%low

Compare Hartford's Climate with Cities Worldwide