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September Weather in Dover, United States

Last updated: June 24, 2025

In September, the average temperature in Dover, United States hovers around 18°C (65°F), with minimums dipping to 4°C (40°F) and soaring to a maximum of 33°C (91°F). Expect about 75 mm (2.9 in) of precipitation spread over 7 days, coupled with an average humidity of 71%. Stay prepared for a mix of pleasant warmth and occasional rain!

September Temperature in Dover

In September, in Dover, the average temperature is 18°C (65°F). Maximum temperatures can reach 33°C (91°F), while minimums can drop as low as 4°C (40°F). This variation makes Dover an ideal destination, offering pleasant days for outdoor activities and cooler evenings for cozy relaxation.

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 18°C (65°F), with highs reaching up to 33°C (91°F) and lows dropping to around 4°C (40°F).
JanFebMarAprMayJunJulAugSepOctNovDec283035465767727265544132
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 75 mm (2.9 in) over a span 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 75 mm (2.9 inches) of precipitation spread over approximately 7 days.
JanFebMarAprMayJunJulAugSepOctNovDec77938513175841317775132107130
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 71%. With an average temperature of 18°C (65°F), this humidity feels like a warm embrace, making it a bit sticky and muggy, which can be slightly uncomfortable for traveling, especially if you're engaging in outdoor activities or exploring the city on foot.

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 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 Dover

In Dover 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 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 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec2457910997532
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 Weather-2°C (28°F)77 mm (3.0 inches)86%low
February Weather-1°C (30°F)93 mm (3.7 inches)84%moderate
March Weather2°C (36°F)85 mm (3.4 inches)82%moderate
April Weather8°C (46°F)131 mm (5.1 inches)80%high
May Weather14°C (57°F)74 mm (2.9 inches)72%very high
June Weather19°C (67°F)84 mm (3.3 inches)72%very high
July Weather22°C (72°F)131 mm (5.2 inches)67%very high
August Weather22°C (72°F)77 mm (3.0 inches)66%very high
September Weather18°C (65°F)75 mm (2.9 inches)71%high
October Weather12°C (54°F)132 mm (5.2 inches)78%moderate
November Weather5°C (41°F)107 mm (4.2 inches)84%moderate
December Weather0°C (32°F)130 mm (5.1 inches)81%low

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