nomadseason

December Weather in Rainier, United States

Last updated: June 24, 2025

In Rainier, United States, the average temperature in December hovers around 5°C (40°F). Expect chilly days where the temperature can dip to a brisk -5°C (24°F) and occasionally reach a mild 14°C (57°F). With an average precipitation of 192 mm (7.6 in) spread over 19 days, be prepared for wet weather. Additionally, the average humidity is a high 87%, adding to the cool, damp atmosphere of the season.

December Temperature in Rainier

In December in Rainier, the average temperature is 5°C (40°F), with maximums reaching up to 14°C (57°F) and minimums dropping as low as -5°C (24°F). Travelers should be prepared for chilly conditions and pack accordingly for both warmth and comfort.

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

The chart illustrates December temperature patterns in Rainier, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Rainier, December typically has an average temperature of 5°C (40°F), with highs reaching up to 14°C (57°F) and lows dropping to around -5°C (24°F).
JanFebMarAprMayJunJulAugSepOctNovDec414045505661656661514540
Data source: Temperature data for Rainier generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

December Precipitation in Rainier

In Rainier in December, the precipitation amount is 192 mm (7.6 in) spread over 19 days, indicating a relatively wet period for the region.

December Precipitation Trends in Rainier

The chart displays monthly precipitation patterns in Rainier, 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 Rainier, December typically receives around 192 mm (7.6 inches) of precipitation spread over approximately 19 days.
JanFebMarAprMayJunJulAugSepOctNovDec183166145119716091079117172192
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

December Humidity in Rainier

In Rainier in December, humidity is 87%. With an average temperature of 5°C (40°F), this humidity feels like a damp chill that wraps around you, making outdoor excursions less enjoyable and requiring extra layers to stay comfortable while exploring.

December Average Humidity in Rainier

This chart illustrates the average monthly humidity levels in Rainier, 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 Rainier is approximately 87%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%84%85%83%83%84%82%74%71%81%87%87%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Rainier

In Rainier in December, 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 Rainier, you can visit Hourly UV Index in Rainier.

Maximum UV Index Levels in Rainier for December

The chart shows the monthly maximum UV Index (UVI) for Rainier 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 Rainier typically reaches 2, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec23569101087532
Data source: Rainier 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 Rainier Compares to Other Months

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

This table compares monthly weather conditions in Rainier, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather5°C (41°F)183 mm (7.2 inches)85%low
February Weather4°C (40°F)166 mm (6.5 inches)84%moderate
March Weather7°C (45°F)145 mm (5.7 inches)85%moderate
April Weather10°C (50°F)119 mm (4.7 inches)83%high
May Weather13°C (56°F)71 mm (2.8 inches)83%very high
June Weather16°C (61°F)59 mm (2.3 inches)83%very high
July Weather18°C (65°F)9 mm (0.4 inches)82%very high
August Weather19°C (66°F)9 mm (0.4 inches)74%very high
September Weather16°C (62°F)79 mm (3.1 inches)71%high
October Weather11°C (51°F)117 mm (4.6 inches)81%moderate
November Weather7°C (45°F)172 mm (6.8 inches)87%moderate
December Weather5°C (40°F)192 mm (7.6 inches)87%low

Compare Rainier's Climate with Cities Worldwide