Merrillville Weather in December
Average highs run from 41°F on December 1 to 33°F on December 31, and lows from 28°F to 20°F. Normal precipitation for the month is 2.58 in over about 11 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
- 37°F
- Average low
- 24°F
- Precipitation
- 2.58 in
- Snowfall
- 9.4 in
- Record high
- 70°FDec 3, 1982
- Record low
- -21°FDec 25, 1983
- Chance of a freeze
- 100%
- Daylight
- 9 h 24 min to 9 h 13 min
- Cloud cover
- 70%
- Humidity
- 86%
- Dew point
- 25°F
- Wind
- 12.1 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 | 41°F | 28°F | 66°F 1970 | 1°F 1958 | 35% | 8% |
| Dec 2 | 41°F | 28°F | 65°F 1982 | 4°F 1966 | 35% | 8% |
| Dec 3 | 41°F | 27°F | 70°F 1982 | 1°F 1976 | 35% | 9% |
| Dec 4 | 40°F | 27°F | 70°F 2012 | 1°F 1991 | 35% | 9% |
| Dec 5 | 40°F | 27°F | 67°F 1998 | 1°F 1991 | 35% | 10% |
| Dec 6 | 39°F | 26°F | 67°F 2001 | -1°F 1964 | 36% | 10% |
| Dec 7 | 39°F | 26°F | 60°F 1980 | -2°F 2005 | 36% | 10% |
| Dec 8 | 39°F | 26°F | 62°F 1966 | -4°F 1958 | 36% | 11% |
| Dec 9 | 38°F | 26°F | 62°F 1991 | -14°F 1958 | 36% | 11% |
| Dec 10 | 38°F | 25°F | 62°F 1971 | -10°F 1958 | 36% | 12% |
| Dec 11 | 38°F | 25°F | 58°F 2021 | -8°F 1972 | 36% | 12% |
| Dec 12 | 37°F | 25°F | 56°F 1990 | -8°F 1962 | 36% | 13% |
| Dec 13 | 37°F | 24°F | 61°F 2015 | -9°F 1958 | 36% | 13% |
| Dec 14 | 37°F | 24°F | 62°F 1975 | -5°F 1985 | 37% | 13% |
| Dec 15 | 37°F | 24°F | 62°F 1971 | -10°F 1958 | 37% | 14% |
| Dec 16 | 36°F | 24°F | 64°F 1975 | -8°F 1989 | 37% | 14% |
| Dec 17 | 36°F | 23°F | 61°F 1984 | -8°F 1989 | 37% | 15% |
| Dec 18 | 36°F | 23°F | 55°F 1957 | -9°F 1985 | 37% | 15% |
| Dec 19 | 36°F | 23°F | 56°F 1957 | -12°F 1983 | 37% | 16% |
| Dec 20 | 35°F | 23°F | 57°F 1967 | -13°F 1963 | 37% | 16% |
| Dec 21 | 35°F | 22°F | 61°F 1967 | -15°F 1989 | 37% | 17% |
| Dec 22 | 35°F | 22°F | 56°F 1957 | -18°F 1989 | 37% | 17% |
| Dec 23 | 35°F | 22°F | 54°F 1982 | -16°F 1960 | 37% | 18% |
| Dec 24 | 35°F | 22°F | 60°F 1982 | -19°F 1983 | 37% | 18% |
| Dec 25 | 34°F | 21°F | 61°F 1982 | -21°F 1983 | 37% | 19% |
| Dec 26 | 34°F | 21°F | 62°F 1982 | -11°F 1983 | 37% | 19% |
| Dec 27 | 34°F | 21°F | 62°F 2019 | -5°F 1983 | 38% | 20% |
| Dec 28 | 34°F | 21°F | 65°F 2008 | -6°F 2017 | 38% | 20% |
| Dec 29 | 34°F | 20°F | 65°F 1984 | -8°F 1983 | 38% | 21% |
| Dec 30 | 33°F | 20°F | 58°F 1965 | -10°F 1983 | 38% | 21% |
| Dec 31 | 33°F | 20°F | 60°F 1965 | -15°F 1967 | 38% | 21% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (CST).
- December 1
- sunrise 6:56 AM, sunset 4:20 PM
- December 31
- sunrise 7:16 AM, sunset 4:29 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00128999 (Valparaiso Wtr Wks), public domain. Records: NOAA GHCN-Daily, station USC00116616, 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.