December weather in Westby, MT
The average temperature in Westby in December is 13.7°F (3.8°F–23.7°F). Average precipitation: 0.48 inches.
December is a winter month in Westby, and is cooler than the annual average of 39.1°F. Daily temperatures swing about 19.9°F between overnight low and afternoon high. Daylight averages about 8h 3m. For travel, December is cold.
Avg High
23.7°F
Avg Low
3.8°F
Precipitation
0.48 in
Daylight
8h 3m
December records in Westby
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| December 1 | 55.0°F (1969) | -18.0°F (1978) | 0.12 in (1964) |
| December 2 | 53.1°F (1949) | -22.0°F (2014) | 0.40 in (1982) |
| December 3 | 54.0°F (1943) | -20.0°F (1978) | 0.25 in (1951) |
| December 4 | 55.0°F (1939) | -27.0°F (1972) | 0.32 in (1948) |
| December 5 | 55.9°F (1939) | -25.1°F (1994) | 0.56 in (2016) |
| December 6 | 61.0°F (1939) | -29.9°F (1956) | 0.24 in (1937) |
| December 7 | 53.1°F (2023) | -31.0°F (2022) | 0.55 in (1945) |
| December 8 | 57.0°F (1939) | -29.0°F (1972) | 0.17 in (2012) |
| December 9 | 54.0°F (1939) | -35.0°F (1977) | 0.19 in (2019) |
| December 10 | 54.0°F (2015) | -25.1°F (1977) | 0.23 in (1949) |
| December 11 | 55.0°F (1939) | -20.9°F (1961) | 0.20 in (1952) |
| December 12 | 48.0°F (1969) | -26.0°F (1940) | 0.27 in (1975) |
| December 13 | 48.0°F (2017) | -24.0°F (1989) | 0.28 in (1973) |
| December 14 | 50.0°F (1939) | -27.0°F (1961) | 0.25 in (1948) |
| December 15 | 53.1°F (1939) | -36.9°F (2009) | 0.34 in (1948) |
| December 16 | 53.1°F (1939) | -31.0°F (1951) | 0.35 in (1977) |
| December 17 | 48.9°F (1939) | -31.0°F (1945) | 0.32 in (1970) |
| December 18 | 52.0°F (1997) | -32.1°F (1989) | 0.15 in (2002) |
| December 19 | 50.0°F (1979) | -34.1°F (1989) | 0.25 in (1960) |
| December 20 | 50.0°F (2004) | -35.0°F (1989) | 0.20 in (2008) |
| December 21 | 48.0°F (2020) | -36.0°F (1989) | 0.21 in (2015) |
| December 22 | 50.0°F (1954) | -35.0°F (1989) | 0.45 in (1969) |
| December 23 | 46.9°F (1953) | -42.0°F (1983) | 0.23 in (2015) |
| December 24 | 42.1°F (1953) | -32.1°F (1983) | 0.32 in (1949) |
| December 25 | 48.0°F (1943) | -32.1°F (1996) | 0.60 in (1950) |
| December 26 | 44.1°F (1972) | -31.0°F (1990) | 0.25 in (1959) |
| December 27 | 53.1°F (1980) | -31.0°F (1990) | 0.12 in (2021) |
| December 28 | 46.9°F (1999) | -31.0°F (2017) | 0.34 in (2003) |
| December 29 | 51.1°F (1999) | -34.1°F (1938) | 0.30 in (1947) |
| December 30 | 46.9°F (1999) | -35.0°F (1968) | 0.95 in (1965) |
| December 31 | 48.9°F (1963) | -32.1°F (1967) | 0.87 in (1975) |