Mason County Weather in December
Average highs run from 46°F on December 1 to 44°F on December 31, and lows from 36°F to 35°F. Normal precipitation for the month is 16.21 in over about 20 wet days.
December day by day
The normal high and low for each date, and the record, in °F.
- Normal low
- Normal high
- Record high
- Record low
December at a glance
- Average high
- 44°F
- Average low
- 35°F
- Precipitation
- 16.21 in
- Snowfall
- 1.7 in
- Record high
- 60°FDec 10, 2014
- Record low
- 6°FDec 9, 2009
- Chance of a freeze
- 97%
- Daylight
- 8 h 45 min to 8 h 32 min
- Cloud cover
- 75%
- Humidity
- 94%
- Dew point
- 33°F
- Wind
- 4.3 mph
Every day of the month
A wet day has at least 0.01 inch of precipitation; snow means at least 0.1 inch of snowfall.
| Date | Normal high | Normal low | Record high | Record low | Chance wet | Chance of snow |
|---|---|---|---|---|---|---|
| Dec 1 | 46°F | 36°F | 54°F 2021 | 15°F 2014 | 66% | 1% |
| Dec 2 | 46°F | 36°F | 54°F 2020 | 17°F 2014 | 66% | 2% |
| Dec 3 | 46°F | 36°F | 59°F 2007 | 21°F 2013 | 66% | 2% |
| Dec 4 | 45°F | 36°F | 59°F 2023 | 16°F 2013 | 66% | 2% |
| Dec 5 | 45°F | 36°F | 59°F 2023 | 14°F 2013 | 66% | 2% |
| Dec 6 | 45°F | 36°F | 55°F 2017 | 19°F 2018 | 66% | 2% |
| Dec 7 | 45°F | 35°F | 55°F 2020 | 8°F 2013 | 66% | 2% |
| Dec 8 | 45°F | 35°F | 59°F 2015 | 8°F 2009 | 66% | 2% |
| Dec 9 | 45°F | 35°F | 59°F 2014 | 6°F 2009 | 66% | 2% |
| Dec 10 | 44°F | 35°F | 60°F 2014 | 7°F 2009 | 66% | 2% |
| Dec 11 | 44°F | 35°F | 55°F 2014 | 9°F 2009 | 66% | 2% |
| Dec 12 | 44°F | 35°F | 56°F 1998 | 9°F 2009 | 66% | 2% |
| Dec 13 | 44°F | 35°F | 55°F 1998 | 19°F 2011 | 66% | 2% |
| Dec 14 | 44°F | 35°F | 54°F 2002 | 24°F 2000 | 66% | 2% |
| Dec 15 | 44°F | 35°F | 58°F 2025 | 17°F 2008 | 66% | 2% |
| Dec 16 | 44°F | 35°F | 55°F 2025 | 9°F 2008 | 66% | 3% |
| Dec 17 | 44°F | 35°F | 53°F 1999 | 15°F 2016 | 66% | 3% |
| Dec 18 | 44°F | 35°F | 55°F 2024 | 22°F 2008 | 66% | 3% |
| Dec 19 | 44°F | 35°F | 53°F 2019 | 18°F 2008 | 66% | 3% |
| Dec 20 | 44°F | 35°F | 55°F 2014 | 13°F 1998 | 66% | 3% |
| Dec 21 | 44°F | 35°F | 56°F 2020 | 13°F 1998 | 66% | 3% |
| Dec 22 | 44°F | 35°F | 54°F 2005 | 6°F 1998 | 66% | 3% |
| Dec 23 | 44°F | 35°F | 54°F 2005 | 8°F 1998 | 66% | 3% |
| Dec 24 | 44°F | 35°F | 59°F 2005 | 23°F 2001 | 66% | 3% |
| Dec 25 | 44°F | 35°F | 56°F 2005 | 22°F 2001 | 66% | 3% |
| Dec 26 | 44°F | 35°F | 55°F 2022 | 21°F 2021 | 66% | 3% |
| Dec 27 | 44°F | 35°F | 53°F 2004 | 10°F 2021 | 66% | 3% |
| Dec 28 | 44°F | 35°F | 53°F 2011 | 24°F 2021 | 67% | 3% |
| Dec 29 | 44°F | 35°F | 55°F 2017 | 15°F 2021 | 67% | 2% |
| Dec 30 | 44°F | 35°F | 52°F 2000 | 19°F 2010 | 67% | 2% |
| Dec 31 | 44°F | 35°F | 54°F 2019 | 13°F 2021 | 67% | 2% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (PST).
- December 1
- sunrise 7:39 AM, sunset 4:24 PM
- December 31
- sunrise 8:00 AM, sunset 4:32 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00451939 (Cushman Powerhouse #2), public domain. Records: NOAA GHCN-Daily, station USW00094227, every year on file, quality-flagged values removed. Cloud, humidity, wind and sunshine: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.