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September Weather in Dover, United States

Last updated: June 24, 2025

In September, the average temperature in Dover, United States is a pleasant 23°C (74°F). While daytime highs can soar to 36°C (97°F), the nights can be refreshingly cool, with minimums dipping down to 11°C (51°F). However, be prepared for some rain—109 mm (4.3 in) of precipitation is expected over a span of 7 days. With an average humidity of 75%, it's a month that beautifully balances warmth and moisture.

September Temperature in Dover

In September in Dover, the average temperature is 23°C (74°F). Maximum temperatures can reach 36°C (97°F), while minimums can drop as low as 11°C (51°F). This makes Dover an ideal destination for travelers seeking pleasant weather with a mix of warm days and cooler evenings.

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

The chart illustrates September temperature patterns in Dover, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Dover, September typically has an average temperature of 23°C (74°F), with highs reaching up to 36°C (97°F) and lows dropping to around 11°C (51°F).
JanFebMarAprMayJunJulAugSepOctNovDec394352597077817874634845
Data source: Temperature data for Dover 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 Dover

In Dover in September, the precipitation amount is 109 mm (4.3 in) over a period of 7 days.

September Precipitation Trends in Dover

The chart displays monthly precipitation patterns in Dover, 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 Dover, September typically receives around 109 mm (4.3 inches) of precipitation spread over approximately 7 days.
JanFebMarAprMayJunJulAugSepOctNovDec10016615215412710810511110912194126
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Dover

In Dover in September, humidity is 75%. With an average temperature of 23°C (74°F), this humidity feels like a warm, heavy blanket wrapping around you, making it feel more sweltering than it actually is, which can be quite uncomfortable for traveling.

September Average Humidity in Dover

This chart illustrates the average monthly humidity levels in Dover, 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 Dover is approximately 75%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%84%84%80%82%83%80%76%75%75%85%88%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Dover

In Dover in September, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Dover.

Maximum UV Index Levels in Dover for September

The chart shows the monthly maximum UV Index (UVI) for Dover 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 Dover typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec36710101111109753
Data source: Dover 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 Dover Compares to Other Months

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

This table compares monthly weather conditions in Dover, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather4°C (40°F)100 mm (3.9 inches)86%moderate
February Weather6°C (43°F)166 mm (6.5 inches)84%high
March Weather11°C (52°F)152 mm (6.0 inches)84%high
April Weather15°C (59°F)154 mm (6.0 inches)80%very high
May Weather21°C (70°F)127 mm (5.0 inches)82%very high
June Weather25°C (77°F)107 mm (4.2 inches)83%extreme
July Weather27°C (81°F)105 mm (4.1 inches)79%extreme
August Weather26°C (79°F)111 mm (4.4 inches)76%very high
September Weather23°C (74°F)109 mm (4.3 inches)75%very high
October Weather17°C (63°F)121 mm (4.8 inches)74%high
November Weather9°C (48°F)94 mm (3.7 inches)85%moderate
December Weather7°C (45°F)126 mm (4.9 inches)88%moderate

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