December Weather in Mattawa, United States

Last updated: June 24, 2025

In December, the average temperature in Mattawa, United States hovers around 0°C (33°F), with a minimum chill of -12°C (11°F) and an occasional warm peak at 18°C (64°F). Expect around 38 mm (1.5 in) of precipitation across 9 days, and stay prepared for a high average humidity of 88%, making it feel quite brisk!

December Temperature in Mattawa

In December in Mattawa, the average temperature is 0°C (33°F). Maximums can reach 18°C (64°F), while minimums can dip as low as -12°C (11°F). This weather makes it essential for travelers to be prepared for cold conditions, with warm clothing and layers being a must.

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

The chart illustrates December temperature patterns in Mattawa, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Mattawa, December typically has an average temperature of 0°C (33°F), with highs reaching up to 18°C (64°F) and lows dropping to around -12°C (11°F).
JanFebMarAprMayJunJulAugSepOctNovDec313243526370777766514033
Data source: Temperature data for Mattawa 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 Mattawa

In Mattawa in December, the total precipitation amount is 38 mm (1.5 in) spread over a duration of 9 days.

December Precipitation Trends in Mattawa

The chart displays monthly precipitation patterns in Mattawa, 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 Mattawa, December typically receives around 38 mm (1.5 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec454328261771514333538
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

December Humidity in Mattawa

In Mattawa in December, humidity is 88%. With an average temperature of 0°C (33°F), this humidity feels like a damp chill that seeps into your bones, making travel uncomfortable and requiring extra layers to stay warm and dry.

December Average Humidity in Mattawa

This chart illustrates the average monthly humidity levels in Mattawa, 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 Mattawa is approximately 88%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%86%87%84%81%82%79%63%62%83%89%88%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Mattawa

In Mattawa 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 Mattawa, you can visit Hourly UV Index in Mattawa.

Maximum UV Index Levels in Mattawa for December

The chart shows the monthly maximum UV Index (UVI) for Mattawa 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 Mattawa typically reaches 2, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec2356891097532
Data source: Mattawa 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 Mattawa Compares to Other Months

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

This table compares monthly weather conditions in Mattawa, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-1°C (31°F)45 mm (1.8 inches)86%low
February Weather0°C (33°F)43 mm (1.7 inches)86%moderate
March Weather6°C (43°F)27 mm (1.1 inches)87%moderate
April Weather11°C (52°F)26 mm (1.0 inches)84%high
May Weather17°C (63°F)17 mm (0.7 inches)81%very high
June Weather21°C (70°F)7 mm (0.3 inches)82%very high
July Weather25°C (77°F)1 mm (0.0 inches)79%very high
August Weather25°C (77°F)5 mm (0.2 inches)63%very high
September Weather19°C (66°F)14 mm (0.5 inches)62%high
October Weather11°C (51°F)33 mm (1.3 inches)83%moderate
November Weather4°C (40°F)35 mm (1.4 inches)89%moderate
December Weather0°C (33°F)38 mm (1.5 inches)88%low

Compare Mattawa's Climate with Cities Worldwide