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September Weather in Northwest Harwinton, United States

Last updated: June 24, 2025

In September, the average temperature in Northwest Harwinton, United States is 19°C (66°F), with fluctuations ranging from a cool 3°C (38°F) to a warm 33°C (92°F). Expect about 122 mm (4.8 in) of precipitation over 9 days, coupled with an average humidity level of 68%. This blend of temperatures and moisture makes September a unique experience in Northwest Harwinton!

September Temperature in Northwest Harwinton

In September in Northwest Harwinton, the average temperature is 19°C (66°F). Maximum temperatures can reach 33°C (92°F), while minimums can dip as low as 3°C (38°F). This variety in weather makes Northwest Harwinton an ideal destination for travelers seeking both warm and cool experiences.

September Weather in Northwest Harwinton: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Northwest Harwinton, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Northwest Harwinton, September typically has an average temperature of 19°C (66°F), with highs reaching up to 33°C (92°F) and lows dropping to around 3°C (38°F).
JanFebMarAprMayJunJulAugSepOctNovDec293237485968747266554133
Data source: Temperature data for Northwest Harwinton 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 Northwest Harwinton

In Northwest Harwinton in September, the precipitation amount is 122 mm (4.8 in) over a span of 9 days.

September Precipitation Trends in Northwest Harwinton

The chart displays monthly precipitation patterns in Northwest Harwinton, 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 Northwest Harwinton, September typically receives around 122 mm (4.8 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec73939113612010316210712215295123
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Northwest Harwinton

In Northwest Harwinton in September humidity is 68%. With an average temperature of 19°C (66°F), this humidity feels like a warm embrace, creating a sticky atmosphere that can be a bit uncomfortable for traveling.

September Average Humidity in Northwest Harwinton

This chart illustrates the average monthly humidity levels in Northwest Harwinton, 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 Northwest Harwinton 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 Northwest Harwinton

In Northwest Harwinton 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 Northwest Harwinton.

Maximum UV Index Levels in Northwest Harwinton for September

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

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

This table compares monthly weather conditions in Northwest Harwinton, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-2°C (29°F)73 mm (2.9 inches)84%moderate
February Weather0°C (32°F)93 mm (3.7 inches)82%moderate
March Weather3°C (38°F)91 mm (3.6 inches)81%high
April Weather9°C (48°F)136 mm (5.3 inches)78%very high
May Weather15°C (59°F)120 mm (4.7 inches)69%very high
June Weather20°C (69°F)103 mm (4.1 inches)69%very high
July Weather23°C (74°F)162 mm (6.4 inches)62%very high
August Weather22°C (73°F)107 mm (4.2 inches)65%very high
September Weather19°C (66°F)122 mm (4.8 inches)68%very high
October Weather13°C (56°F)152 mm (6.0 inches)74%high
November Weather5°C (42°F)95 mm (3.7 inches)82%moderate
December Weather1°C (33°F)123 mm (4.9 inches)80%low

Compare Northwest Harwinton's Climate with Cities Worldwide