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September Weather in Amherst, United States

Last updated: June 24, 2025

In Amherst, United States, the average temperature in September hovers around 23°C (73°F), creating a pleasant atmosphere for outdoor activities. Temperatures can vary, with a minimum of 3°C (38°F) and reaching up to a sizzling 38°C (101°F). Expect a bit of rain, with an average precipitation of 44 mm (1.7 in) over 6 days, and the air remains fairly humid with an average humidity level of 71%.

September Temperature in Amherst

In September in Amherst, the average temperature is 23°C (73°F). Maximum temperatures can reach 38°C (101°F), while minimums can drop as low as 3°C (38°F). This makes Amherst an ideal destination for travelers seeking warm weather with a chance to experience cooler evenings, so be sure to pack accordingly!

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 23°C (73°F), with highs reaching up to 38°C (101°F) and lows dropping to around 3°C (38°F).
JanFebMarAprMayJunJulAugSepOctNovDec404354607078817973605043
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 total precipitation amount is 44 mm (1.7 in) spread over 6 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 44 mm (1.7 inches) of precipitation spread over approximately 6 days.
JanFebMarAprMayJunJulAugSepOctNovDec161135224938313944631615
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 71%. With an average temperature of 23°C (73°F), this humidity feels like a warm, sticky embrace, making outdoor exploration slightly uncomfortable but still manageable if you stay hydrated and plan for breaks in shaded areas.

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 71%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec75%75%61%61%67%69%69%66%71%71%82%80%
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 reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. 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 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec579111112121210864
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 Weather5°C (41°F)16 mm (0.6 inches)75%moderate
February Weather6°C (44°F)11 mm (0.4 inches)74%high
March Weather12°C (54°F)35 mm (1.4 inches)61%very high
April Weather16°C (60°F)22 mm (0.9 inches)61%extreme
May Weather21°C (70°F)49 mm (1.9 inches)67%extreme
June Weather26°C (78°F)38 mm (1.5 inches)69%extreme
July Weather27°C (81°F)31 mm (1.2 inches)69%extreme
August Weather26°C (79°F)39 mm (1.5 inches)66%extreme
September Weather23°C (73°F)44 mm (1.7 inches)71%very high
October Weather15°C (60°F)63 mm (2.5 inches)71%very high
November Weather10°C (50°F)16 mm (0.6 inches)82%high
December Weather6°C (44°F)15 mm (0.6 inches)80%moderate

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