January Weather in Portola, United States

Last updated: June 24, 2025

In January, the average temperature in Portola, United States hovers around -1°C (31°F), with lows dipping to a chilling -19°C (-1°F) and highs reaching up to a mild 13°C (56°F). Expect a precipitation amount of 170 mm (6.7 in) spread over 11 days, and be prepared for a relatively high average humidity of 84%.

January Temperature in Portola

In January in Portola, the average temperature is -1°C (31°F), with maximums reaching 13°C (56°F) and minimums dropping to as low as -19°C (-1°F). Be prepared for a wide range of temperatures during your travels, as you may experience both chilly and milder days.

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

The chart illustrates January temperature patterns in Portola, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Portola, January typically has an average temperature of -1°C (31°F), with highs reaching up to 13°C (56°F) and lows dropping to around -19°C (-1°F).

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

January Precipitation in Portola

In Portola in January, the precipitation amount is 170 mm (6.7 in) over the course of 11 days.

January Precipitation Trends in Portola

The chart displays monthly precipitation patterns in Portola, 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 Portola, January typically receives around 170 mm (6.7 inches) of precipitation spread over approximately 11 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 Portola

In Portola in January humidity is 84%. With an average temperature of -1°C (31°F), this humidity feels like a biting chill that seeps through layers of clothing, making outdoor excursions brisk and invigorating, yet challenging for those unaccustomed to such damp conditions.

January Average Humidity in Portola

This chart illustrates the average monthly humidity levels in Portola, 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 Portola 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 Portola

In Portola in January, the maximum UV index reaches 4, which corresponds to a moderate Exposure Category. With a time to burn of 30 minutes, it’s important to take precautions to protect your skin. You can find more details in the Hourly UV Index in Portola for better planning.

Maximum UV Index Levels in Portola for January

The chart shows the monthly maximum UV Index (UVI) for Portola 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 Portola typically reaches 4, which falls under the moderate exposure category.

Data source: Portola 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 Portola Compares to Other Months

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

This table compares monthly weather conditions in Portola, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-1°C (31°F)	170 mm (6.7 inches)	84%	moderate
February Weather	-1°C (30°F)	177 mm (7.0 inches)	84%	high
March Weather	1°C (34°F)	146 mm (5.7 inches)	83%	very high
April Weather	5°C (41°F)	72 mm (2.8 inches)	81%	very high
May Weather	10°C (51°F)	60 mm (2.3 inches)	74%	extreme
June Weather	16°C (62°F)	10 mm (0.4 inches)	64%	extreme
July Weather	21°C (70°F)	10 mm (0.4 inches)	44%	extreme
August Weather	20°C (68°F)	13 mm (0.5 inches)	36%	extreme
September Weather	15°C (60°F)	19 mm (0.7 inches)	44%	very high
October Weather	8°C (47°F)	43 mm (1.7 inches)	65%	high
November Weather	3°C (38°F)	79 mm (3.1 inches)	84%	moderate
December Weather	-2°C (29°F)	132 mm (5.2 inches)	83%	moderate