January Weather in South Portland, United States

Last updated: June 24, 2025

In South Portland, United States during January, the average temperature hovers around -2°C (28°F). Expect chilly conditions, with minimum temperatures plummeting to -19°C (-2°F), while the maximum can reach a milder 12°C (54°F). Be prepared for some rainfall, with a total precipitation of 97 mm (3.8 in) spread over 9 days, and a notable average humidity level of 86%.

January Temperature in South Portland

In January in South Portland, the average temperature is -2°C (28°F). The maximum can reach 12°C (54°F), while the minimum can drop as low as -19°C (-2°F). Travelers should be prepared for a wide range of temperatures, making warm clothing essential for outdoor activities.

January Weather in South Portland: Daily Temperature Highs, Lows, and Averages

The chart illustrates January temperature patterns in South Portland, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In South Portland, January typically has an average temperature of -2°C (28°F), with highs reaching up to 12°C (54°F) and lows dropping to around -19°C (-2°F).

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

January Precipitation in South Portland

In South Portland in January, the total precipitation amount reaches 97 mm (3.8 in) over the course of 9 days.

January Precipitation Trends in South Portland

The chart displays monthly precipitation patterns in South Portland, 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 South Portland, January typically receives around 97 mm (3.8 inches) of precipitation spread over approximately 9 days.

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

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Millimeters (mm) Inches (in)

January Humidity in South Portland

In South Portland in January, humidity is 86%. With an average temperature of -2°C (28°F), this humidity feels like a dense fog wrapping around you, making it feel even colder and creating an uncomfortable chill that can dampen any plans for outdoor exploration.

January Average Humidity in South Portland

This chart illustrates the average monthly humidity levels in South Portland, 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 South Portland is approximately 86%, 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 South Portland

In South Portland in January, the maximum UV index is 2, which corresponds to a low exposure category. With this level of UV radiation, the time to burn is approximately 45 minutes. To learn more about the hourly UV index in South Portland, you can visit Hourly UV Index in South Portland.

Maximum UV Index Levels in South Portland for January

The chart shows the monthly maximum UV Index (UVI) for South Portland 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 South Portland typically reaches 2, which falls under the low exposure category.

Data source: South Portland 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 South Portland Compares to Other Months

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

This table compares monthly weather conditions in South Portland, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-2°C (28°F)	97 mm (3.8 inches)	86%	low
February Weather	-2°C (29°F)	103 mm (4.1 inches)	84%	moderate
March Weather	1°C (34°F)	91 mm (3.6 inches)	82%	moderate
April Weather	6°C (43°F)	149 mm (5.9 inches)	80%	high
May Weather	11°C (52°F)	94 mm (3.7 inches)	72%	very high
June Weather	17°C (62°F)	80 mm (3.2 inches)	72%	very high
July Weather	20°C (68°F)	123 mm (4.9 inches)	67%	very high
August Weather	20°C (69°F)	75 mm (3.0 inches)	66%	very high
September Weather	17°C (63°F)	77 mm (3.0 inches)	71%	high
October Weather	12°C (54°F)	163 mm (6.4 inches)	78%	moderate
November Weather	5°C (42°F)	130 mm (5.1 inches)	84%	moderate
December Weather	0°C (33°F)	144 mm (5.7 inches)	81%	low