December weather in Rock Island, WA
The average temperature in Rock Island in December is 29.0°F (24.5°F–33.4°F). Average precipitation: 1.31 inches.
December is a winter month in Rock Island, and is cooler than the annual average of 51.2°F. Daily temperatures swing about 8.9°F between overnight low and afternoon high. Expect about 11 days with precipitation. Daylight averages about 8h 16m. For travel, December is cold.
Avg High
33.4°F
Avg Low
24.5°F
Precipitation
1.31 in
Daylight
8h 16m
December records in Rock Island
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| December 1 | 70.0°F (2021) | -4.0°F (1985) | 0.41 in (1966) |
| December 2 | 57.9°F (1975) | 8.1°F (1985) | 0.78 in (1980) |
| December 3 | 57.0°F (1975) | 6.1°F (1984) | 0.40 in (2007) |
| December 4 | 55.0°F (1975) | 5.0°F (1984) | 0.34 in (1967) |
| December 5 | 48.9°F (2025) | 8.1°F (1984) | 0.34 in (2015) |
| December 6 | 54.0°F (1979) | 5.0°F (1980) | 0.27 in (1977) |
| December 7 | 51.1°F (1973) | 3.0°F (1972) | 0.80 in (1996) |
| December 8 | 52.0°F (1991) | -0.9°F (1972) | 0.84 in (1963) |
| December 9 | 52.0°F (2015) | 3.0°F (1972) | 1.12 in (1987) |
| December 10 | 68.0°F (2025) | 1.9°F (2009) | 0.64 in (1992) |
| December 11 | 62.1°F (2025) | 3.9°F (1972) | 0.83 in (2010) |
| December 12 | 51.1°F (2025) | 6.1°F (1972) | 0.67 in (1971) |
| December 13 | 53.1°F (1979) | 3.9°F (1972) | 0.56 in (1977) |
| December 14 | 57.9°F (1979) | 6.1°F (1972) | 0.98 in (2006) |
| December 15 | 59.0°F (2025) | -2.9°F (1964) | 0.70 in (1970) |
| December 16 | 57.9°F (1999) | -11.0°F (1964) | 0.54 in (1961) |
| December 17 | 52.0°F (1998) | -11.9°F (1964) | 0.37 in (2024) |
| December 18 | 52.0°F (1976) | -2.9°F (1964) | 0.28 in (1960) |
| December 19 | 48.9°F (2004) | -4.0°F (1984) | 0.44 in (1981) |
| December 20 | 51.1°F (2020) | -7.1°F (2008) | 0.36 in (1970) |
| December 21 | 55.0°F (1974) | -6.9°F (2022) | 0.71 in (1964) |
| December 22 | 51.1°F (2014) | -9.0°F (1983) | 0.60 in (1964) |
| December 23 | 46.0°F (2013) | -15.0°F (1983) | 0.49 in (1979) |
| December 24 | 48.0°F (2014) | -0.9°F (1983) | 0.44 in (1988) |
| December 25 | 50.0°F (1963) | 3.9°F (1983) | 0.42 in (1980) |
| December 26 | 55.9°F (1980) | 5.0°F (1990) | 0.48 in (1996) |
| December 27 | 57.0°F (1980) | 1.0°F (1996) | 0.65 in (1965) |
| December 28 | 52.0°F (2011) | -16.1°F (1968) | 0.37 in (1992) |
| December 29 | 53.1°F (1997) | -20.0°F (1968) | 0.96 in (1996) |
| December 30 | 48.0°F (2011) | -20.9°F (1968) | 0.36 in (2022) |
| December 31 | 48.9°F (1998) | -13.0°F (1968) | 0.75 in (1996) |