Waterloo weather in December: Waterloo, Iowa: normal highs, lows, rain and records for December
Waterloo in December has a normal high of 34°F and a normal low of 17°F, a daily mean of 25°F, falling from 39°F on the 1st to 29°F by the 31st. Measurable precipitation falls on 8 days in a normal December, 1.44 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 1°C and low of −8°C, 37 mm of precipitation and 25 cm of snow in December.
- NOAA stationWaterloo Municipal Airport
- Station IDUSW00094910
- Location42.55°N 92.40°W
- Elevation868 ft (265 m)
- Population67,477
- Jan 28° 11°
- Feb 33° 15°
- Mar 47° 27°
- Apr 61° 38°
- May 73° 50°
- Jun 82° 61°
- Jul 85° 64°
- Aug 83° 61°
- Sep 77° 52°
- Oct 63° 40°
- Nov 47° 28°
- Dec 34° 17°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Waterloo in December?
The normal high is 34°F and the normal low 17°F, for a daily mean of 25.3°F. December is 12.1°F cooler than November and 5.9°F warmer than January. December is the 10th warmest month of the year in Waterloo and the 10th wettest. Across the month the normal high falls 10°F, from 39°F on December 1 to 29°F on December 31. From one year to the next December's mean temperature typically moves about 5.7°F either way (NOAA's standard deviation), so roughly two Decembers in three average between 20°F and 31°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 28%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| December 1 | 39°F | 22°F | 27% | 13% |
| December 8 | 36°F | 19°F | 27% | 13% |
| December 15 | 34°F | 17°F | 27% | 12% |
| December 22 | 32°F | 15°F | 27% | 12% |
| December 31 | 29°F | 13°F | 27% | 11% |
Every day of December: normal high, low and chance of precipitation (warmest afternoon December 1, coldest night December 31)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| December 1 | 39°F | 22°F | 27% | 13% | 9 h 20 min |
| December 2 | 39°F | 21°F | 27% | 13% | 9 h 20 min |
| December 3 | 39°F | 21°F | 28% | 13% | 9 h 20 min |
| December 4 | 38°F | 21°F | 27% | 13% | 9 h 20 min |
| December 5 | 38°F | 20°F | 27% | 13% | 9 h 10 min |
| December 6 | 37°F | 20°F | 27% | 13% | 9 h 10 min |
| December 7 | 37°F | 20°F | 27% | 13% | 9 h 10 min |
| December 8 | 36°F | 19°F | 27% | 13% | 9 h 10 min |
| December 9 | 36°F | 19°F | 27% | 13% | 9 h 10 min |
| December 10 | 36°F | 19°F | 27% | 12% | 9 h 10 min |
| December 11 | 35°F | 18°F | 27% | 12% | 9 h 10 min |
| December 12 | 35°F | 18°F | 27% | 12% | 9 h 10 min |
| December 13 | 34°F | 18°F | 27% | 12% | 9 h 10 min |
| December 14 | 34°F | 18°F | 27% | 12% | 9 h 10 min |
| December 15 | 34°F | 17°F | 27% | 12% | 9 h 10 min |
| December 16 | 33°F | 17°F | 27% | 12% | 9 h |
| December 17 | 33°F | 17°F | 27% | 12% | 9 h |
| December 18 | 33°F | 16°F | 27% | 12% | 9 h |
| December 19 | 32°F | 16°F | 27% | 12% | 9 h |
| December 20 | 32°F | 16°F | 27% | 12% | 9 h |
| December 21 | 32°F | 15°F | 27% | 12% | 9 h |
| December 22 | 32°F | 15°F | 27% | 12% | 9 h |
| December 23 | 31°F | 15°F | 27% | 11% | 9 h |
| December 24 | 31°F | 15°F | 27% | 11% | 9 h |
| December 25 | 31°F | 14°F | 27% | 11% | 9 h |
| December 26 | 30°F | 14°F | 27% | 11% | 9 h |
| December 27 | 30°F | 14°F | 27% | 11% | 9 h |
| December 28 | 30°F | 14°F | 27% | 11% | 9 h |
| December 29 | 30°F | 13°F | 27% | 11% | 9 h |
| December 30 | 30°F | 13°F | 27% | 11% | 9 h 10 min |
| December 31 | 29°F | 13°F | 27% | 11% | 9 h 10 min |
- Normal high
- 34°FDecember average
- Normal low
- 17°FDecember average
- Precipitation
- 1.44 inmonth total
- Days with precipitation
- 80.01 inch or more
- Snowfall
- 9.9 inmonth total
- Nights at 32°F or colder
- 29
- Daylight
- 9 h 20 min to 9 h 10 minDecember 1 to December 31
- Sunshine
- 66%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00094910; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain or snow in Waterloo in December?
On a given December day the chance of 0.01 inch or more is 27% on average, highest around December 3 (28%). In all, 1.44 in falls on 8 days of a normal December.
In a normal December in Waterloo, 29 nights fall to freezing, 14 days stay below freezing all day and snowfall averages 9.9 inches.
Snow falls on 6 days in a normal December, and an inch or more covers the ground on 13 days.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00094910.
How humid and windy is Waterloo in December?
At 3 p.m. the normal temperature is 26°F with 70% relative humidity and a dew point of 17°F; at 6 a.m. it is 18°F with 83% humidity. The wind averages 10.0 mph, most often from the west in the afternoon. A dew point under 50°F feels dry.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 18°F | 13°F | 83% | 9.1 mph | 47% |
| 9 a.m. | 19°F | 14°F | 82% | 10.0 mph | 52% |
| noon | 24°F | 16°F | 73% | 11.6 mph | 43% |
| 3 p.m. | 26°F | 17°F | 70% | 12.0 mph | 52% |
| 6 p.m. | 22°F | 17°F | 78% | 9.6 mph | 50% |
| 9 p.m. | 21°F | 16°F | 81% | 9.5 mph | 58% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00094910. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).
What are the records for December in Waterloo?
The warmest December temperature on Waterloo's official record (since 1895) is 74°F, on December 15, 2021; the coldest is −29°F, on December 10, 1919. The wettest December brought 5.92 in (2015); the snowiest, 33.9 inches (2000).
The December mean against the 1991-2020 normal of 25.3°F: 2021 31.4°F (+6.1), 2022 22.0°F (−3.3), 2023 34.8°F (+9.5), 2024 28.8°F (+3.5), 2025 20.9°F (−4.4). 3 of 5 ran warmer than normal.
| December | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 31.4°F | +6.1°F | 1.32 in |
| 2022 | 22.0°F | −3.3°F | 1.59 in |
| 2023 | 34.8°F | +9.5°F | 0.85 in |
| 2024 | 28.8°F | +3.5°F | 1.45 in |
| 2025 | 20.9°F | −4.4°F | 0.58 in |
Source: records: ACIS, NWS threaded record ALOthr; recent months: ACIS, station USW00094910. Records and recent months use complete months only.
How does December in Waterloo compare across Iowa?
Across the 132 places PlainClimate covers in Iowa, December normal highs run from 27°F in Northwood to 38°F in Keokuk; Waterloo's is 34°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.