December weather in Union City, CA
The average temperature in Union City in December is 50.5°F (42.5°F–58.4°F). Average precipitation: 2.97 inches.
December is a winter month in Union City, and is cooler than the annual average of 59.5°F. Daily temperatures swing about 15.9°F between overnight low and afternoon high. Expect about 10 days with precipitation. Daylight averages about 9h 25m. For travel, December is a comfortable month to visit.
Avg High
58.4°F
Avg Low
42.5°F
Precipitation
2.97 in
Daylight
9h 25m
December records in Union City
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| December 1 | 71.1°F (2021) | 34.0°F (2004) | 0.58 in (2022) |
| December 2 | 71.1°F (2011) | 30.9°F (2022) | 1.00 in (2014) |
| December 3 | 66.9°F (2011) | 36.0°F (1996) | 1.30 in (2014) |
| December 4 | 68.0°F (2014) | 32.0°F (2004) | 0.45 in (2022) |
| December 5 | 69.1°F (2002) | 30.0°F (2013) | 1.40 in (1996) |
| December 6 | 69.1°F (2014) | 30.9°F (2013) | 0.26 in (1998) |
| December 7 | 70.0°F (2020) | 32.0°F (1998) | 0.63 in (1997) |
| December 8 | 72.0°F (2020) | 30.0°F (2009) | 0.69 in (2004) |
| December 9 | 68.0°F (2015) | 32.0°F (2009) | 0.16 in (2006) |
| December 10 | 69.1°F (2012) | 28.9°F (2013) | 1.27 in (2016) |
| December 11 | 70.0°F (1996) | 33.1°F (2013) | 2.10 in (2014) |
| December 12 | 69.1°F (1996) | 33.1°F (2013) | 1.10 in (2014) |
| December 13 | 66.9°F (2004) | 30.9°F (2022) | 0.66 in (2021) |
| December 14 | 64.9°F (2017) | 32.0°F (2022) | 1.06 in (2021) |
| December 15 | 66.9°F (1998) | 34.0°F (2013) | 1.11 in (2014) |
| December 16 | 73.0°F (1998) | 30.9°F (2022) | 1.14 in (2002) |
| December 17 | 72.0°F (1998) | 30.9°F (2022) | 0.65 in (2014) |
| December 18 | 68.0°F (1998) | 30.0°F (2016) | 1.31 in (2005) |
| December 19 | 64.0°F (2000) | 30.0°F (2016) | 1.33 in (2023) |
| December 20 | 66.9°F (2005) | 33.1°F (2008) | 1.62 in (2002) |
| December 21 | 66.0°F (2005) | 28.9°F (1998) | 1.77 in (1996) |
| December 22 | 66.0°F (2013) | 28.9°F (1998) | 0.73 in (2015) |
| December 23 | 68.0°F (2014) | 27.0°F (1998) | 1.55 in (2012) |
| December 24 | 69.1°F (2005) | 27.0°F (1998) | 0.54 in (2024) |
| December 25 | 66.9°F (2013) | 30.0°F (1998) | 0.61 in (2008) |
| December 26 | 66.9°F (2013) | 30.9°F (1997) | 0.63 in (2005) |
| December 27 | 64.9°F (2001) | 30.0°F (2015) | 1.55 in (2022) |
| December 28 | 68.0°F (1997) | 33.1°F (2016) | 0.85 in (2001) |
| December 29 | 66.9°F (2013) | 32.0°F (2015) | 0.94 in (2001) |
| December 30 | 64.0°F (1996) | 33.1°F (2015) | 0.91 in (2023) |
| December 31 | 66.9°F (1996) | 34.0°F (2012) | 3.08 in (2022) |