January Weather in Marietta-Alderwood, United States

Last updated: June 24, 2025

In January, the average temperature in Marietta-Alderwood, United States hovers around 5°C (41°F). Expect a chilly minimum of -7°C (20°F), while the mercury may rise to a comfortable 13°C (56°F). With 199 mm (7.8 in) of precipitation falling over about 15 days, be prepared for some wet weather. Additionally, the air carries an average humidity of 86%, ensuring a brisk and damp atmosphere.

January Temperature in Marietta-Alderwood

In January in Marietta-Alderwood, the average temperature is 5°C (41°F). The maximum can reach 13°C (56°F), and the minimum can be as low as -7°C (20°F). Be sure to pack warm clothing if you plan to visit during this time.

January Weather in Marietta-Alderwood: Daily Temperature Highs, Lows, and Averages

The chart illustrates January temperature patterns in Marietta-Alderwood, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Marietta-Alderwood, January typically has an average temperature of 5°C (41°F), with highs reaching up to 13°C (56°F) and lows dropping to around -7°C (20°F).

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

January Precipitation in Marietta-Alderwood

In Marietta-Alderwood in January, the precipitation amount reaches 199 mm (7.8 in) over a span of 15 days.

January Precipitation Trends in Marietta-Alderwood

The chart displays monthly precipitation patterns in Marietta-Alderwood, 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 Marietta-Alderwood, January typically receives around 199 mm (7.8 inches) of precipitation spread over approximately 15 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 Marietta-Alderwood

In Marietta-Alderwood in January humidity is 86%. With an average temperature of 5°C (41°F), this humidity feels like a heavy, damp blanket wrapping around you, making outdoor activities uncomfortable and travel quite challenging due to the chill combined with the stickiness in the air.

January Average Humidity in Marietta-Alderwood

This chart illustrates the average monthly humidity levels in Marietta-Alderwood, 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 Marietta-Alderwood 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 Marietta-Alderwood

In Marietta-Alderwood 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 Marietta-Alderwood, you can visit Hourly UV Index in Marietta-Alderwood.

Maximum UV Index Levels in Marietta-Alderwood for January

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

Data source: Marietta-Alderwood 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 Marietta-Alderwood Compares to Other Months

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

This table compares monthly weather conditions in Marietta-Alderwood, 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 (41°F)	199 mm (7.8 inches)	86%	low
February Weather	4°C (39°F)	185 mm (7.3 inches)	85%	moderate
March Weather	6°C (44°F)	156 mm (6.2 inches)	86%	moderate
April Weather	9°C (48°F)	127 mm (5.0 inches)	86%	high
May Weather	12°C (53°F)	76 mm (3.0 inches)	81%	very high
June Weather	15°C (59°F)	58 mm (2.3 inches)	83%	very high
July Weather	17°C (63°F)	27 mm (1.1 inches)	84%	very high
August Weather	18°C (64°F)	19 mm (0.8 inches)	77%	very high
September Weather	15°C (60°F)	125 mm (4.9 inches)	76%	high
October Weather	11°C (51°F)	186 mm (7.3 inches)	88%	moderate
November Weather	8°C (46°F)	261 mm (10.3 inches)	87%	low
December Weather	5°C (41°F)	227 mm (8.9 inches)	87%	low