January Weather in Sussex, United States

Last updated: June 24, 2025

In Sussex, United States, the average temperature in January hovers around 5°C (42°F). During this time, temperatures can vary significantly, with minimums dipping to -20°C (-3°F) and maximums reaching up to 24°C (75°F). Expect a total precipitation of 84 mm (3.3 in) spread across 9 days, contributing to an average humidity level of 84%. Be prepared for a diverse climate!

January Temperature in Sussex

In January in Sussex, the average temperature is 5°C (42°F), with maximums reaching 24°C (75°F) and minimums dropping as low as -20°C (-3°F). It's essential to pack layers and be prepared for a wide range of weather conditions during your travels.

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

The chart illustrates January 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, January typically has an average temperature of 5°C (42°F), with highs reaching up to 24°C (75°F) and lows dropping to around -20°C (-3°F).

Data source: Temperature data for Sussex generated using information from the Copernicus Climate Change Service.

January Precipitation in Sussex

In Sussex in January, the precipitation amount is 84 mm (3.3 in) spread over 9 days.

January Precipitation Trends in Sussex

The chart displays monthly precipitation patterns in Sussex, with values for each month alongside January’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how January’s conditions compare to those of other months. In Sussex, January typically receives around 84 mm (3.3 inches) of precipitation spread over approximately 9 days.

Data source: Precipitation data for January generated using information from the Copernicus Climate Change Service.

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

January Humidity in Sussex

In Sussex in January, humidity is 84%. With an average temperature of 5°C (42°F), this humidity feels like a thick blanket wrapping around you, making every step feel heavier while traveling.

January Average Humidity in Sussex

This chart illustrates the average monthly humidity levels in Sussex, with January’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In January, average humidity in Sussex is approximately 84%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for January generated using information from the Copernicus Climate Change Service.

January UV Index in Sussex

In Sussex in January, 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 January

The chart shows the monthly maximum UV Index (UVI) for Sussex in January, 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 January, the maximum UV index in Sussex typically reaches 3, which falls under the moderate exposure category.

Data source: Sussex January 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 January 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 January’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 January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	5°C (42°F)	84 mm (3.3 inches)	84%	moderate
February Weather	8°C (47°F)	105 mm (4.2 inches)	83%	high
March Weather	10°C (51°F)	85 mm (3.4 inches)	82%	high
April Weather	16°C (61°F)	109 mm (4.3 inches)	81%	very high
May Weather	21°C (69°F)	115 mm (4.5 inches)	80%	very high
June Weather	24°C (76°F)	116 mm (4.6 inches)	82%	very high
July Weather	27°C (81°F)	124 mm (4.9 inches)	81%	extreme
August Weather	26°C (79°F)	161 mm (6.3 inches)	81%	very high
September Weather	23°C (74°F)	113 mm (4.4 inches)	78%	very high
October Weather	18°C (65°F)	104 mm (4.1 inches)	80%	very high
November Weather	10°C (51°F)	78 mm (3.1 inches)	84%	moderate
December Weather	7°C (45°F)	89 mm (3.5 inches)	84%	moderate