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September Weather in Hopkinton, United States

Last updated: June 24, 2025

In September, the average temperature in Hopkinton, United States hovers around 17°C (64°F). Be prepared for a range of temperatures: it can drop to a chilly 0°C (33°F) or soar to a warm 33°C (92°F). Expect some rain, with an average precipitation of 76 mm (3.0 in) spread over 8 days, and enjoy the moderate humidity level at around 71%.

September Temperature in Hopkinton

In September in Hopkinton, the average temperature is 17°C (64°F). Maximums can reach 33°C (92°F) and minimums can be as low as 0°C (33°F). Overall, it’s advisable to pack layers to comfortably enjoy the varied temperatures while traveling.

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

The chart illustrates September temperature patterns in Hopkinton, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Hopkinton, September typically has an average temperature of 17°C (64°F), with highs reaching up to 33°C (92°F) and lows dropping to around 0°C (33°F).
JanFebMarAprMayJunJulAugSepOctNovDec242734455767727163523828
Data source: Temperature data for Hopkinton 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 Hopkinton

In Hopkinton in September, the precipitation amount is 76 mm (3.0 in) spread over a duration of 8 days.

September Precipitation Trends in Hopkinton

The chart displays monthly precipitation patterns in Hopkinton, 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 Hopkinton, September typically receives around 76 mm (3.0 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec70837712778851369376130105115
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Hopkinton

In Hopkinton in September humidity is 71%. With an average temperature of 17°C (64°F), this humidity feels like a warm, enveloping embrace that can make travel feel a bit sticky, yet still pleasant as you explore the sights with a gentle sheen of perspiration.

September Average Humidity in Hopkinton

This chart illustrates the average monthly humidity levels in Hopkinton, 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 Hopkinton is approximately 71%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%84%82%80%72%72%67%66%71%79%84%81%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Hopkinton

In Hopkinton 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 Hopkinton.

Maximum UV Index Levels in Hopkinton for September

The chart shows the monthly maximum UV Index (UVI) for Hopkinton 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 Hopkinton typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3458910997532
Data source: Hopkinton 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 Hopkinton Compares to Other Months

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

This table compares monthly weather conditions in Hopkinton, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-4°C (25°F)70 mm (2.8 inches)86%moderate
February Weather-3°C (27°F)83 mm (3.3 inches)84%moderate
March Weather1°C (34°F)77 mm (3.0 inches)82%moderate
April Weather7°C (45°F)127 mm (5.0 inches)80%very high
May Weather14°C (57°F)78 mm (3.1 inches)72%very high
June Weather20°C (68°F)85 mm (3.4 inches)72%very high
July Weather22°C (73°F)136 mm (5.3 inches)67%very high
August Weather21°C (71°F)93 mm (3.7 inches)66%very high
September Weather17°C (64°F)76 mm (3.0 inches)71%high
October Weather11°C (52°F)130 mm (5.1 inches)78%moderate
November Weather3°C (38°F)105 mm (4.1 inches)84%moderate
December Weather-2°C (29°F)115 mm (4.5 inches)81%low

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