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September Weather in Westerly, United States

Last updated: June 24, 2025

In September, the average temperature in Westerly, United States hovers around 19°C (67°F). However, temperatures can swing between a chilly 7°C (45°F) and a warm 31°C (88°F). Be prepared for some wet days, as the region typically sees about 93 mm (3.7 in) of precipitation over 9 days. With an average humidity of 75%, it's a month that combines warmth with a touch of moisture.

September Temperature in Westerly

In September in Westerly, the average temperature is 19°C (67°F). Maximum temperatures can reach 31°C (88°F), while minimums can drop as low as 7°C (45°F). This makes Westerly an ideal destination for travelers looking to enjoy mild weather with the possibility of warm afternoons and cool evenings.

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

The chart illustrates September temperature patterns in Westerly, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Westerly, September typically has an average temperature of 19°C (67°F), with highs reaching up to 31°C (88°F) and lows dropping to around 7°C (45°F).
JanFebMarAprMayJunJulAugSepOctNovDec333539485867747367584537
Data source: Temperature data for Westerly 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 Westerly

In Westerly in September, the precipitation amount is 93 mm (3.7 in) over the course of 9 days.

September Precipitation Trends in Westerly

The chart displays monthly precipitation patterns in Westerly, 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 Westerly, September typically receives around 93 mm (3.7 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec73951011251119512810293134100125
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Westerly

In Westerly in September humidity is 75%. With an average temperature of 19°C (67°F), this humidity feels like a warm embrace, making travel invigorating yet slightly sticky, as you navigate through the vibrant streets or scenic landscapes.

September Average Humidity in Westerly

This chart illustrates the average monthly humidity levels in Westerly, 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 Westerly is approximately 75%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%84%82%79%75%78%76%76%76%75%80%80%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Westerly

In Westerly 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 Westerly.

Maximum UV Index Levels in Westerly for September

The chart shows the monthly maximum UV Index (UVI) for Westerly 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 Westerly typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3568910998642
Data source: Westerly 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 Westerly Compares to Other Months

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

This table compares monthly weather conditions in Westerly, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather0°C (33°F)73 mm (2.9 inches)84%moderate
February Weather2°C (35°F)95 mm (3.7 inches)84%moderate
March Weather4°C (39°F)101 mm (4.0 inches)82%high
April Weather9°C (48°F)125 mm (4.9 inches)79%very high
May Weather14°C (58°F)111 mm (4.4 inches)75%very high
June Weather20°C (68°F)95 mm (3.7 inches)78%very high
July Weather23°C (74°F)128 mm (5.0 inches)76%very high
August Weather23°C (74°F)102 mm (4.0 inches)76%very high
September Weather19°C (67°F)93 mm (3.7 inches)75%very high
October Weather14°C (58°F)134 mm (5.3 inches)75%high
November Weather7°C (46°F)100 mm (3.9 inches)80%moderate
December Weather3°C (37°F)125 mm (4.9 inches)80%low

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