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September Weather in Dover, United States

Last updated: June 24, 2025

In Dover, United States, the average temperature in September is a mild 18°C (64°F). Expect daily temperatures to range from a cool 2°C (35°F) to a warm 32°C (91°F). During this month, you can anticipate approximately 121 mm (4.8 in) of precipitation over 9 days, contributing to an average humidity level of 74%. Prepare for a blend of comfortable warmth and occasional showers as you explore!

September Temperature in Dover

In September in Dover, the average temperature is 18°C (64°F). The maximum can reach 32°C (91°F), while the minimum can dip as low as 2°C (35°F). This makes it essential for travelers to pack both light clothing for the warm days and warmer layers for the 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 18°C (64°F), with highs reaching up to 32°C (91°F) and lows dropping to around 2°C (35°F).
JanFebMarAprMayJunJulAugSepOctNovDec171834435870737064483425
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 121 mm (4.8 in) over the course of 9 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 121 mm (4.8 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec36475887145139991221211134942
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 74%. With an average temperature of 18°C (64°F), this humidity feels like a warm embrace, making it ideal for leisurely strolls but potentially uncomfortable for extended outdoor activities.

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 74%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%85%84%83%75%79%75%69%74%79%88%82%
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 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 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 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec35589101098532
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-8°C (18°F)36 mm (1.4 inches)84%moderate
February Weather-8°C (19°F)47 mm (1.9 inches)85%moderate
March Weather1°C (34°F)58 mm (2.3 inches)84%moderate
April Weather6°C (44°F)87 mm (3.4 inches)83%very high
May Weather15°C (59°F)145 mm (5.7 inches)75%very high
June Weather21°C (71°F)139 mm (5.5 inches)79%very high
July Weather23°C (73°F)99 mm (3.9 inches)75%very high
August Weather21°C (70°F)122 mm (4.8 inches)69%very high
September Weather18°C (64°F)121 mm (4.8 inches)74%very high
October Weather9°C (48°F)113 mm (4.5 inches)79%moderate
November Weather1°C (34°F)49 mm (1.9 inches)88%moderate
December Weather-4°C (25°F)42 mm (1.7 inches)82%low

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