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December Weather in Sunnyside, United States

Last updated: June 24, 2025

In December, the average temperature in Sunnyside, United States hovers around 1°C (35°F). Expect a range of temperatures, with a chilling minimum of -10°C (15°F) and a comfortable maximum of 20°C (68°F). With 35 mm (1.4 in) of precipitation spread over 8 days, it's a good idea to pack your umbrella. Don’t forget, the average humidity is quite high at 88%, so be prepared for a damp atmosphere!

December Temperature in Sunnyside

In December in Sunnyside, the average temperature is 1°C (35°F). Maximums can reach 20°C (68°F), while minimums can drop as low as -10°C (15°F). This wide temperature range suggests that travelers should be prepared for both chilly and milder days during their visit.

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

The chart illustrates December temperature patterns in Sunnyside, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Sunnyside, December typically has an average temperature of 1°C (35°F), with highs reaching up to 20°C (68°F) and lows dropping to around -10°C (15°F).
JanFebMarAprMayJunJulAugSepOctNovDec343645546573807968534235
Data source: Temperature data for Sunnyside generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

December Precipitation in Sunnyside

In Sunnyside in December, the precipitation amount is 35 mm (1.4 in) over the course of 8 days.

December Precipitation Trends in Sunnyside

The chart displays monthly precipitation patterns in Sunnyside, 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 Sunnyside, December typically receives around 35 mm (1.4 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec43432524167159263135
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Sunnyside

In Sunnyside in December, humidity is 88%. With an average temperature of 1°C (35°F), this humidity feels like a chilly embrace, making travel quite uncomfortable as the cold moisture clings to your skin, leaving you feeling damp and frigid.

December Average Humidity in Sunnyside

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

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

Maximum UV Index Levels in Sunnyside for December

The chart shows the monthly maximum UV Index (UVI) for Sunnyside 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 Sunnyside typically reaches 2, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec23569101097532
Data source: Sunnyside 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 Sunnyside Compares to Other Months

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

This table compares monthly weather conditions in Sunnyside, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather1°C (34°F)43 mm (1.7 inches)86%low
February Weather2°C (36°F)43 mm (1.7 inches)86%moderate
March Weather7°C (45°F)25 mm (1.0 inches)87%moderate
April Weather12°C (54°F)24 mm (1.0 inches)84%high
May Weather18°C (65°F)16 mm (0.6 inches)81%very high
June Weather23°C (73°F)7 mm (0.3 inches)82%very high
July Weather27°C (80°F)1 mm (0.0 inches)79%very high
August Weather26°C (79°F)5 mm (0.2 inches)63%very high
September Weather20°C (68°F)9 mm (0.4 inches)62%high
October Weather12°C (53°F)26 mm (1.0 inches)83%moderate
November Weather5°C (42°F)31 mm (1.2 inches)89%moderate
December Weather1°C (35°F)35 mm (1.4 inches)88%low

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