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September Weather in Grafton, United States

Last updated: June 24, 2025

In September, the average temperature in Grafton, United States is a pleasant 19°C (67°F). Expect temperatures to range from a chilly 4°C (39°F) to a warm 32°C (89°F). With an average humidity of 73%, you might also experience some rain, as 113 mm (4.5 in) of precipitation usually falls over about 9 days.

September Temperature in Grafton

In September in Grafton, the average temperature is 19°C (67°F). Maximums can reach 32°C (89°F), and minimums can drop as low as 4°C (39°F). This temperature variation makes Grafton a versatile destination ideal for travelers seeking both warm days and cooler evenings.

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 19°C (67°F), with highs reaching up to 32°C (89°F) and lows dropping to around 4°C (39°F).
JanFebMarAprMayJunJulAugSepOctNovDec333843526369737267574338
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 113 mm (4.5 in) over a span of 9 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 113 mm (4.5 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec10215912215216014511511411312089134
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 73%. With an average temperature of 19°C (67°F), this humidity feels like a warm blanket wrapped around you, making travel slightly uncomfortable and sticky, but still manageable as long as you stay hydrated and take breaks in the shade.

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 73%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%88%88%87%82%84%82%73%74%81%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.
JanFebMarAprMayJunJulAugSepOctNovDec3579101010108753
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 Weather0°C (33°F)102 mm (4.0 inches)88%moderate
February Weather3°C (38°F)159 mm (6.2 inches)88%moderate
March Weather6°C (44°F)122 mm (4.8 inches)88%high
April Weather11°C (53°F)152 mm (6.0 inches)86%very high
May Weather17°C (63°F)160 mm (6.3 inches)82%very high
June Weather20°C (69°F)145 mm (5.7 inches)84%very high
July Weather23°C (74°F)115 mm (4.5 inches)82%very high
August Weather22°C (72°F)114 mm (4.5 inches)73%very high
September Weather19°C (67°F)113 mm (4.5 inches)73%very high
October Weather14°C (58°F)120 mm (4.7 inches)81%high
November Weather6°C (43°F)89 mm (3.5 inches)89%moderate
December Weather3°C (38°F)134 mm (5.3 inches)86%moderate

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