Casper weather in December: Casper, Wyoming: normal highs, lows, rain and records for December
Casper in December has a normal high of 35°F and a normal low of 15°F, a daily mean of 25°F, falling from 38°F on the 1st to 34°F by the 31st. Measurable precipitation falls on 7 days in a normal December, 0.61 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 2°C and low of −10°C, 15 mm of precipitation and 28 cm of snow in December.
- NOAA stationCasper-Natrona County Airport
- Station IDUSW00024089
- Location42.90°N 106.46°W
- Elevation5,338 ft (1,627 m)
- Population58,823
- Jan 35° 15°
- Feb 38° 15°
- Mar 49° 23°
- Apr 56° 28°
- May 67° 37°
- Jun 80° 45°
- Jul 89° 53°
- Aug 87° 51°
- Sep 76° 42°
- Oct 60° 31°
- Nov 46° 22°
- Dec 35° 15°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Casper in December?
The normal high is 35°F and the normal low 15°F, for a daily mean of 24.8°F. December is 9.2°F cooler than November and 0.3°F cooler than January. December is the 12th warmest month of the year in Casper and the 10th wettest, and the snowiest. Across the month the normal high falls 4°F, from 38°F on December 1 to 34°F on December 31. From one year to the next December's mean temperature typically moves about 3.7°F either way (NOAA's standard deviation), so roughly two Decembers in three average between 21°F and 29°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 22%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| December 1 | 38°F | 17°F | 22% | 7% |
| December 8 | 36°F | 16°F | 22% | 7% |
| December 15 | 34°F | 14°F | 22% | 6% |
| December 22 | 34°F | 14°F | 22% | 6% |
| December 31 | 34°F | 14°F | 21% | 6% |
Every day of December: normal high, low and chance of precipitation (warmest afternoon December 1, coldest night December 21)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| December 1 | 38°F | 17°F | 22% | 7% | 9 h 20 min |
| December 2 | 38°F | 17°F | 22% | 7% | 9 h 20 min |
| December 3 | 37°F | 17°F | 22% | 7% | 9 h 10 min |
| December 4 | 37°F | 17°F | 22% | 7% | 9 h 10 min |
| December 5 | 37°F | 16°F | 22% | 7% | 9 h 10 min |
| December 6 | 36°F | 16°F | 22% | 7% | 9 h 10 min |
| December 7 | 36°F | 16°F | 22% | 7% | 9 h 10 min |
| December 8 | 36°F | 16°F | 22% | 7% | 9 h 10 min |
| December 9 | 35°F | 15°F | 22% | 7% | 9 h 10 min |
| December 10 | 35°F | 15°F | 22% | 6% | 9 h 10 min |
| December 11 | 35°F | 15°F | 22% | 6% | 9 h 10 min |
| December 12 | 35°F | 15°F | 22% | 6% | 9 h |
| December 13 | 34°F | 15°F | 22% | 6% | 9 h |
| December 14 | 34°F | 14°F | 22% | 6% | 9 h |
| December 15 | 34°F | 14°F | 22% | 6% | 9 h |
| December 16 | 34°F | 14°F | 22% | 6% | 9 h |
| December 17 | 34°F | 14°F | 22% | 6% | 9 h |
| December 18 | 34°F | 14°F | 22% | 6% | 9 h |
| December 19 | 34°F | 14°F | 22% | 6% | 9 h |
| December 20 | 34°F | 14°F | 22% | 6% | 9 h |
| December 21 | 34°F | 14°F | 22% | 6% | 9 h |
| December 22 | 34°F | 14°F | 22% | 6% | 9 h |
| December 23 | 34°F | 14°F | 22% | 6% | 9 h |
| December 24 | 34°F | 14°F | 22% | 6% | 9 h |
| December 25 | 34°F | 14°F | 22% | 6% | 9 h |
| December 26 | 34°F | 14°F | 21% | 6% | 9 h |
| December 27 | 34°F | 14°F | 21% | 6% | 9 h |
| December 28 | 34°F | 14°F | 21% | 6% | 9 h |
| December 29 | 34°F | 14°F | 21% | 6% | 9 h |
| December 30 | 34°F | 14°F | 21% | 6% | 9 h |
| December 31 | 34°F | 14°F | 21% | 6% | 9 h |
- Normal high
- 35°FDecember average
- Normal low
- 15°FDecember average
- Precipitation
- 0.61 inmonth total
- Days with precipitation
- 70.01 inch or more
- Snowfall
- 11.0 inmonth total
- Nights at 32°F or colder
- 29
- Daylight
- 9 h 20 min to 9 hDecember 1 to December 31
- Sunshine
- 68%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00024089; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain or snow in Casper in December?
On a given December day the chance of 0.01 inch or more is 22% on average, highest around December 15 (22%). In all, 0.61 in falls on 7 days of a normal December.
In a normal December in Casper, 29 nights fall to freezing, 12 days stay below freezing all day and snowfall averages 11.0 inches.
Snow falls on 8 days in a normal December, and an inch or more covers the ground on 16 days.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00024089.
How humid and windy is Casper in December?
At 3 p.m. the normal temperature is 31°F with 54% relative humidity and a dew point of 16°F; at 6 a.m. it is 21°F with 66% humidity. The wind averages 15.5 mph, most often from the southwest in the afternoon. A dew point under 50°F feels dry.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 21°F | 12°F | 66% | 15.0 mph | 69% |
| 9 a.m. | 23°F | 13°F | 63% | 15.9 mph | 68% |
| noon | 29°F | 15°F | 55% | 18.5 mph | 69% |
| 3 p.m. | 31°F | 16°F | 54% | 17.0 mph | 71% |
| 6 p.m. | 25°F | 14°F | 64% | 14.1 mph | 72% |
| 9 p.m. | 23°F | 13°F | 65% | 14.4 mph | 68% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00024089. 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 Casper?
The warmest December temperature on Casper's official record (since 1939) is 66°F, on December 2, 2021; the coldest is −42°F, on December 22, 2022. The wettest December brought 3.71 in (1982); the snowiest, 62.8 inches (1982).
The December mean against the 1991-2020 normal of 24.8°F: 2021 30.1°F (+5.3), 2022 22.8°F (−2.0), 2023 32.0°F (+7.2), 2024 33.4°F (+8.6), 2025 36.9°F (+12.1). 4 of 5 ran warmer than normal.
| December | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 30.1°F | +5.3°F | 0.63 in |
| 2022 | 22.8°F | −2.0°F | 0.74 in |
| 2023 | 32.0°F | +7.2°F | 0.06 in |
| 2024 | 33.4°F | +8.6°F | 0.16 in |
| 2025 | 36.9°F | +12.1°F | 0.36 in |
Source: records: ACIS, NWS threaded record CPRthr; recent months: ACIS, station USW00024089. Records and recent months use complete months only.
How does December in Casper compare across Wyoming?
Across the 71 places PlainClimate covers in Wyoming, December normal highs run from 24°F in Bondurant to 43°F in Yoder; Casper's is 35°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.