Mason City Weather in December
Average highs run from 36°F on December 1 to 25°F on December 31, and lows from 19°F to 10°F. Normal precipitation for the month is 1.25 in over about 8 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
- 30°F
- Average low
- 14°F
- Precipitation
- 1.25 in
- Snowfall
- 9.4 in
- Record high
- 69°FDec 15, 2021
- Record low
- -26°FDec 18, 1983
- Chance of a freeze
- 100%
- Daylight
- 9 h 14 min to 9 h 02 min
- Cloud cover
- 66%
- Humidity
- 87%
- Dew point
- 19°F
- Wind
- 11.9 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 | 36°F | 19°F | 67°F 1998 | -2°F 1983 | 23% | 17% |
| Dec 2 | 35°F | 19°F | 64°F 1998 | -14°F 1985 | 23% | 18% |
| Dec 3 | 35°F | 19°F | 63°F 2012 | -15°F 1985 | 23% | 18% |
| Dec 4 | 34°F | 18°F | 66°F 2017 | -13°F 2025 | 23% | 18% |
| Dec 5 | 34°F | 18°F | 62°F 2001 | -7°F 2005 | 24% | 19% |
| Dec 6 | 33°F | 17°F | 53°F 1951 | -15°F 1976 | 24% | 19% |
| Dec 7 | 33°F | 17°F | 57°F 2024 | -18°F 1972 | 24% | 19% |
| Dec 8 | 33°F | 17°F | 58°F 2024 | -16°F 1958 | 24% | 19% |
| Dec 9 | 32°F | 16°F | 54°F 2020 | -19°F 1958 | 24% | 20% |
| Dec 10 | 32°F | 16°F | 59°F 1979 | -16°F 1978 | 24% | 20% |
| Dec 11 | 31°F | 16°F | 55°F 1949 | -11°F 1976 | 24% | 20% |
| Dec 12 | 31°F | 15°F | 58°F 1968 | -16°F 2000 | 24% | 20% |
| Dec 13 | 31°F | 15°F | 56°F 1998 | -21°F 1961 | 24% | 20% |
| Dec 14 | 30°F | 15°F | 55°F 1998 | -16°F 1972 | 24% | 21% |
| Dec 15 | 30°F | 14°F | 69°F 2021 | -16°F 1963 | 24% | 21% |
| Dec 16 | 30°F | 14°F | 58°F 1959 | -17°F 1963 | 24% | 21% |
| Dec 17 | 29°F | 14°F | 50°F 1962 | -18°F 1983 | 24% | 21% |
| Dec 18 | 29°F | 14°F | 55°F 1962 | -26°F 1983 | 24% | 22% |
| Dec 19 | 29°F | 13°F | 48°F 1979 | -26°F 1983 | 24% | 22% |
| Dec 20 | 28°F | 13°F | 48°F 1967 | -25°F 1983 | 24% | 22% |
| Dec 21 | 28°F | 13°F | 50°F 1979 | -23°F 1989 | 24% | 22% |
| Dec 22 | 28°F | 12°F | 48°F 2023 | -22°F 1983 | 24% | 23% |
| Dec 23 | 27°F | 12°F | 46°F 1965 | -25°F 1990 | 24% | 23% |
| Dec 24 | 27°F | 12°F | 53°F 2023 | -24°F 1983 | 24% | 23% |
| Dec 25 | 27°F | 11°F | 51°F 2023 | -21°F 2000 | 24% | 23% |
| Dec 26 | 27°F | 11°F | 49°F 1959 | -26°F 1950 | 24% | 23% |
| Dec 27 | 26°F | 11°F | 52°F 1959 | -26°F 1950 | 24% | 23% |
| Dec 28 | 26°F | 11°F | 56°F 1984 | -21°F 1993 | 24% | 24% |
| Dec 29 | 26°F | 10°F | 47°F 1999 | -13°F 1970 | 24% | 24% |
| Dec 30 | 26°F | 10°F | 54°F 1965 | -20°F 1968 | 24% | 24% |
| Dec 31 | 25°F | 10°F | 52°F 1965 | -22°F 1976 | 24% | 24% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (CST).
- December 1
- sunrise 7:25 AM, sunset 4:39 PM
- December 31
- sunrise 7:45 AM, sunset 4:47 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00135230 (Mason City), public domain. Records: NOAA GHCN-Daily, station USW00014940, 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.