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September Weather in Amherst, United States

Last updated: June 24, 2025

In September, the average temperature in Amherst, United States is a pleasant 18°C (65°F). Daily temperatures can vary widely, with minimums dipping to 4°C (40°F) and maximums soaring to 32°C (89°F). Be prepared for some rain, as precipitation amounts to 72 mm (2.8 in) over approximately 9 days. With an average humidity of 76%, it's a perfect time to embrace the season's charm!

September Temperature in Amherst

In September in Amherst, the average temperature is 18°C (65°F). The maximum can reach 32°C (89°F), and the minimum can be as low as 4°C (40°F). This makes it an ideal time for travelers to enjoy a mix of warm days and cool evenings while exploring the area.

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

The chart illustrates September temperature patterns in Amherst, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Amherst, September typically has an average temperature of 18°C (65°F), with highs reaching up to 32°C (89°F) and lows dropping to around 4°C (40°F).
JanFebMarAprMayJunJulAugSepOctNovDec272936465867737165544033
Data source: Temperature data for Amherst 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 Amherst

In Amherst in September, the precipitation amount is 72 mm (2.8 in) over the course of 9 days.

September Precipitation Trends in Amherst

The chart displays monthly precipitation patterns in Amherst, 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 Amherst, September typically receives around 72 mm (2.8 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec768168115987913080721228489
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Amherst

In Amherst in September, humidity is 76%. With an average temperature of 18°C (65°F), this humidity feels like a warm embrace, making travel a little sticky but enjoyable, as long as you stay hydrated and take breaks in the shade.

September Average Humidity in Amherst

This chart illustrates the average monthly humidity levels in Amherst, 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 Amherst is approximately 76%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec91%91%88%88%82%80%77%72%76%83%88%87%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Amherst

In Amherst 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 Amherst.

Maximum UV Index Levels in Amherst for September

The chart shows the monthly maximum UV Index (UVI) for Amherst 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 Amherst typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec2458910997532
Data source: Amherst 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 Amherst Compares to Other Months

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

This table compares monthly weather conditions in Amherst, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-3°C (28°F)76 mm (3.0 inches)91%low
February Weather-2°C (29°F)80 mm (3.2 inches)91%moderate
March Weather2°C (36°F)68 mm (2.7 inches)88%moderate
April Weather8°C (46°F)115 mm (4.5 inches)88%very high
May Weather14°C (58°F)98 mm (3.9 inches)82%very high
June Weather20°C (68°F)79 mm (3.1 inches)79%very high
July Weather23°C (73°F)130 mm (5.1 inches)77%very high
August Weather22°C (72°F)80 mm (3.2 inches)72%very high
September Weather18°C (65°F)72 mm (2.8 inches)76%high
October Weather12°C (55°F)122 mm (4.8 inches)83%moderate
November Weather5°C (41°F)84 mm (3.3 inches)88%moderate
December Weather0°C (33°F)89 mm (3.5 inches)87%low

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