December Weather in Portal, United States

Last updated: June 24, 2025

In Portal, United States, the average temperature in December is 12°C (54°F), with minimums dipping to -4°C (24°F) and maximums reaching up to 27°C (80°F). Expect a total precipitation of 121 mm (4.8 in) spread over 9 days, and enjoy an average humidity level of 87%. Be prepared for a mix of cool, wet days amid the mild temperatures!

December Temperature in Portal

In December in Portal, the average temperature is 12°C (54°F). The maximum can reach 27°C (80°F) and the minimum can be as low as -4°C (24°F). This variety in temperatures makes it essential for travelers to pack layers to enjoy their stay comfortably.

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

The chart illustrates December temperature patterns in Portal, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Portal, December typically has an average temperature of 12°C (54°F), with highs reaching up to 27°C (80°F) and lows dropping to around -4°C (24°F).

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

December Precipitation in Portal

In Portal in December, the precipitation amount is 121 mm (4.8 in) over the course of 9 days.

December Precipitation Trends in Portal

The chart displays monthly precipitation patterns in Portal, 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 Portal, December typically receives around 121 mm (4.8 inches) of precipitation spread over approximately 9 days.

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

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Millimeters (mm) Inches (in)

December Humidity in Portal

In Portal in December humidity is 87%. With an average temperature of 12°C (54°F), this humidity feels like a damp embrace, making it quite uncomfortable for traveling, as the air feels heavy and can quickly sap your energy as you explore the sights.

December Average Humidity in Portal

This chart illustrates the average monthly humidity levels in Portal, 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 Portal is approximately 87%, offering insight into how humid the weather typically is during this month.

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

December UV Index in Portal

In Portal in December, 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 Portal for better planning.

Maximum UV Index Levels in Portal for December

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

Data source: Portal 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 Portal Compares to Other Months

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

This table compares monthly weather conditions in Portal, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	11°C (51°F)	81 mm (3.2 inches)	86%	moderate
February Weather	14°C (57°F)	97 mm (3.8 inches)	81%	high
March Weather	16°C (61°F)	68 mm (2.7 inches)	81%	very high
April Weather	19°C (67°F)	92 mm (3.6 inches)	79%	very high
May Weather	24°C (76°F)	78 mm (3.1 inches)	75%	extreme
June Weather	27°C (80°F)	112 mm (4.4 inches)	75%	extreme
July Weather	28°C (83°F)	127 mm (5.0 inches)	80%	extreme
August Weather	28°C (82°F)	119 mm (4.7 inches)	81%	extreme
September Weather	26°C (79°F)	87 mm (3.4 inches)	83%	very high
October Weather	22°C (72°F)	76 mm (3.0 inches)	78%	very high
November Weather	14°C (58°F)	61 mm (2.4 inches)	85%	high
December Weather	12°C (54°F)	121 mm (4.8 inches)	87%	moderate