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December Weather in Sussex, United States

Last updated: June 24, 2025

In December, the average temperature in Sussex, United States hovers around 7°C (45°F), with fluctuations that can take you from a brisk -9°C (16°F) to a pleasantly warm 23°C (74°F). Prepare for a bit of wet weather, as you'll encounter about 89 mm (3.5 in) of precipitation over 9 days, contributing to an average humidity level of 84%. Stay cozy and embrace the charm of this vibrant season!

December Temperature in Sussex

In December in Sussex, the average temperature is 7°C (45°F), with maximums reaching 23°C (74°F) and minimums dropping as low as -9°C (16°F). It's advisable to pack layers and be prepared for a wide range of temperatures while exploring this destination.

December Weather in Sussex: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Sussex, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Sussex, December typically has an average temperature of 7°C (45°F), with highs reaching up to 23°C (74°F) and lows dropping to around -9°C (16°F).
JanFebMarAprMayJunJulAugSepOctNovDec414651616976807874645145
Data source: Temperature data for Sussex 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.

December Precipitation in Sussex

In Sussex in December, the precipitation amount is 89 mm (3.5 in) during a span of 9 days.

December Precipitation Trends in Sussex

The chart displays monthly precipitation patterns in Sussex, with values for each month alongside December’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how December’s conditions compare to those of other months. In Sussex, December typically receives around 89 mm (3.5 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec84105861091151161241611131047889
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Sussex

In Sussex in December, humidity is 84%. With an average temperature of 7°C (45°F), this humidity feels like a damp chill that seeps into your bones, making travel uncomfortable and necessitating extra layers to stay warm while exploring the sights.

December Average Humidity in Sussex

This chart illustrates the average monthly humidity levels in Sussex, with December’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In December, average humidity in Sussex is approximately 84%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%83%82%81%80%82%81%81%78%80%84%84%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Sussex

In Sussex in December, the maximum UV index is 3, which corresponds to a moderate Exposure Category. The time to burn is approximately 30 minutes. For more details on the hourly UV index in Sussex, you can check the information here.

Maximum UV Index Levels in Sussex for December

The chart shows the monthly maximum UV Index (UVI) for Sussex in December, 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 December, the maximum UV index in Sussex typically reaches 3, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3679101011109853
Data source: Sussex December 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 December Weather in Sussex Compares to Other Months

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

This table compares monthly weather conditions in Sussex, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather5°C (42°F)84 mm (3.3 inches)84%moderate
February Weather8°C (47°F)105 mm (4.2 inches)83%high
March Weather10°C (51°F)85 mm (3.4 inches)82%high
April Weather16°C (61°F)109 mm (4.3 inches)81%very high
May Weather21°C (69°F)115 mm (4.5 inches)80%very high
June Weather24°C (76°F)116 mm (4.6 inches)82%very high
July Weather27°C (81°F)124 mm (4.9 inches)81%extreme
August Weather26°C (79°F)161 mm (6.3 inches)81%very high
September Weather23°C (74°F)113 mm (4.4 inches)78%very high
October Weather18°C (65°F)104 mm (4.1 inches)80%very high
November Weather10°C (51°F)78 mm (3.1 inches)84%moderate
December Weather7°C (45°F)89 mm (3.5 inches)84%moderate

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