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September Weather in Grafton, United States

Last updated: June 24, 2025

In Grafton, United States, the average temperature in September hovers around 20°C (68°F), with a range that can dip to a chilly 5°C (41°F) and peak at a warm 33°C (92°F). Expect 85 mm (3.4 in) of precipitation spread over approximately 11 days, contributing to an average humidity level of 77%.

September Temperature in Grafton

In September in Grafton, the average temperature is 20°C (68°F), with maximums reaching 33°C (92°F) and minimums dropping as low as 5°C (41°F). This climate makes Grafton an ideal destination for travelers seeking a pleasant mix of warm days and cool nights.

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

The chart illustrates September temperature patterns in Grafton, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Grafton, September typically has an average temperature of 20°C (68°F), with highs reaching up to 33°C (92°F) and lows dropping to around 5°C (41°F).
JanFebMarAprMayJunJulAugSepOctNovDec293239496170757267574235
Data source: Temperature data for Grafton 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 Grafton

In Grafton in September, the precipitation amount is 85 mm (3.4 in) over the course of 11 days.

September Precipitation Trends in Grafton

The chart displays monthly precipitation patterns in Grafton, 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 Grafton, September typically receives around 85 mm (3.4 inches) of precipitation spread over approximately 11 days.
JanFebMarAprMayJunJulAugSepOctNovDec80909312012313513097851029188
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Grafton

In Grafton in September, humidity is 77%. With an average temperature of 20°C (68°F), this humidity feels like a warm, sticky embrace, making it essential for travelers to stay hydrated and take breaks in shaded areas to avoid feeling sluggish in the heat.

September Average Humidity in Grafton

This chart illustrates the average monthly humidity levels in Grafton, 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 Grafton is approximately 77%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec89%88%87%87%81%83%82%76%77%82%89%86%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Grafton

In Grafton 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 Grafton.

Maximum UV Index Levels in Grafton for September

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

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

This table compares monthly weather conditions in Grafton, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-1°C (30°F)80 mm (3.1 inches)88%moderate
February Weather0°C (32°F)90 mm (3.5 inches)88%moderate
March Weather4°C (40°F)92 mm (3.6 inches)87%high
April Weather10°C (50°F)120 mm (4.7 inches)87%very high
May Weather16°C (62°F)123 mm (4.9 inches)81%very high
June Weather21°C (71°F)135 mm (5.3 inches)83%very high
July Weather24°C (75°F)130 mm (5.1 inches)82%very high
August Weather22°C (73°F)97 mm (3.8 inches)76%very high
September Weather20°C (68°F)85 mm (3.4 inches)77%very high
October Weather14°C (57°F)102 mm (4.0 inches)82%high
November Weather5°C (42°F)90 mm (3.6 inches)89%moderate
December Weather2°C (35°F)88 mm (3.5 inches)86%low

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