Williamsport weather in December: Williamsport, Pennsylvania: normal highs, lows, rain and records for December
Williamsport in December has a normal high of 40°F and a normal low of 26°F, a daily mean of 33°F, falling from 44°F on the 1st to 36°F by the 31st. Measurable precipitation falls on 12 days in a normal December, 3.27 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 4°C and low of −3°C, 83 mm of precipitation and 18 cm of snow in December.
- NOAA stationWilliamsport Regional Airport
- Station IDUSW00014778
- Location41.24°N 76.92°W
- Elevation520 ft (159 m)
- Population27,628
- Jan 35° 20°
- Feb 39° 22°
- Mar 48° 29°
- Apr 62° 39°
- May 72° 49°
- Jun 81° 58°
- Jul 85° 63°
- Aug 83° 61°
- Sep 75° 54°
- Oct 63° 43°
- Nov 51° 33°
- Dec 40° 26°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Williamsport in December?
The normal high is 40°F and the normal low 26°F, for a daily mean of 32.8°F. December is 9.1°F cooler than November and 5.1°F warmer than January. December is the 10th warmest month of the year in Williamsport and the 8th wettest. Across the month the normal high falls 8°F, from 44°F on December 1 to 36°F on December 31. From one year to the next December's mean temperature typically moves about 3.9°F either way (NOAA's standard deviation), so roughly two Decembers in three average between 29°F and 37°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 39%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| December 1 | 44°F | 29°F | 38% | 21% |
| December 8 | 42°F | 28°F | 38% | 21% |
| December 15 | 40°F | 26°F | 39% | 21% |
| December 22 | 38°F | 24°F | 39% | 20% |
| December 31 | 36°F | 22°F | 39% | 20% |
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 | 44°F | 29°F | 38% | 21% | 9 h 30 min |
| December 2 | 44°F | 29°F | 38% | 21% | 9 h 30 min |
| December 3 | 43°F | 29°F | 38% | 21% | 9 h 20 min |
| December 4 | 43°F | 29°F | 38% | 21% | 9 h 20 min |
| December 5 | 43°F | 28°F | 38% | 21% | 9 h 20 min |
| December 6 | 42°F | 28°F | 38% | 21% | 9 h 20 min |
| December 7 | 42°F | 28°F | 38% | 21% | 9 h 20 min |
| December 8 | 42°F | 28°F | 38% | 21% | 9 h 20 min |
| December 9 | 41°F | 27°F | 39% | 21% | 9 h 20 min |
| December 10 | 41°F | 27°F | 39% | 21% | 9 h 20 min |
| December 11 | 41°F | 27°F | 39% | 21% | 9 h 20 min |
| December 12 | 41°F | 27°F | 39% | 21% | 9 h 20 min |
| December 13 | 40°F | 27°F | 39% | 21% | 9 h 10 min |
| December 14 | 40°F | 26°F | 39% | 21% | 9 h 10 min |
| December 15 | 40°F | 26°F | 39% | 21% | 9 h 10 min |
| December 16 | 39°F | 26°F | 39% | 20% | 9 h 10 min |
| December 17 | 39°F | 26°F | 39% | 20% | 9 h 10 min |
| December 18 | 39°F | 25°F | 39% | 20% | 9 h 10 min |
| December 19 | 39°F | 25°F | 39% | 20% | 9 h 10 min |
| December 20 | 38°F | 25°F | 39% | 20% | 9 h 10 min |
| December 21 | 38°F | 25°F | 39% | 20% | 9 h 10 min |
| December 22 | 38°F | 24°F | 39% | 20% | 9 h 10 min |
| December 23 | 38°F | 24°F | 39% | 20% | 9 h 10 min |
| December 24 | 38°F | 24°F | 39% | 20% | 9 h 10 min |
| December 25 | 37°F | 24°F | 39% | 20% | 9 h 10 min |
| December 26 | 37°F | 24°F | 39% | 20% | 9 h 10 min |
| December 27 | 37°F | 23°F | 39% | 20% | 9 h 10 min |
| December 28 | 37°F | 23°F | 39% | 20% | 9 h 10 min |
| December 29 | 37°F | 23°F | 39% | 20% | 9 h 10 min |
| December 30 | 37°F | 23°F | 39% | 20% | 9 h 10 min |
| December 31 | 36°F | 22°F | 39% | 20% | 9 h 10 min |
- Normal high
- 40°FDecember average
- Normal low
- 26°FDecember average
- Precipitation
- 3.27 inmonth total
- Days with precipitation
- 120.01 inch or more
- Snowfall
- 6.9 inmonth total
- Nights at 32°F or colder
- 24
- Daylight
- 9 h 30 min to 9 h 10 minDecember 1 to December 31
- Sunshine
- 55%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00014778; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain or snow in Williamsport in December?
On a given December day the chance of 0.01 inch or more is 39% on average, highest around December 31 (39%). In all, 3.27 in falls on 12 days of a normal December, 1 of them with an inch or more.
In a normal December in Williamsport, 24 nights fall to freezing, 6 days stay below freezing all day and snowfall averages 6.9 inches.
Snow falls on 5 days in a normal December, and an inch or more covers the ground on 6 days.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00014778.
How humid and windy is Williamsport in December?
At 3 p.m. the normal temperature is 35°F with 57% relative humidity and a dew point of 21°F; at 6 a.m. it is 27°F with 76% humidity. The wind averages 7.0 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. | 27°F | 21°F | 76% | 6.2 mph | 34% |
| 9 a.m. | 28°F | 21°F | 74% | 6.7 mph | 38% |
| noon | 33°F | 22°F | 63% | 8.7 mph | 33% |
| 3 p.m. | 35°F | 21°F | 57% | 9.0 mph | 38% |
| 6 p.m. | 32°F | 21°F | 64% | 6.9 mph | 41% |
| 9 p.m. | 30°F | 21°F | 70% | 6.6 mph | 42% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00014778. 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 Williamsport?
The warmest December temperature on Williamsport's official record (since 1895) is 70°F, on December 1, 2006; the coldest is −15°F, on December 28, 1950. The wettest December brought 7.36 in (1973); the snowiest, 35.5 inches (1969).
The December mean against the 1991-2020 normal of 32.8°F: 2021 38.4°F (+5.6), 2022 32.2°F (−0.6), 2023 39.7°F (+6.9), 2024 32.1°F (−0.7), 2025 28.2°F (−4.6). 2 of 5 ran warmer than normal.
| December | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 38.4°F | +5.6°F | 1.37 in |
| 2022 | 32.2°F | −0.6°F | 5.15 in |
| 2023 | 39.7°F | +6.9°F | 5.19 in |
| 2024 | 32.1°F | −0.7°F | 3.28 in |
| 2025 | 28.2°F | −4.6°F | 2.33 in |
Source: records: ACIS, NWS threaded record IPTthr; recent months: ACIS, station USW00014778. Records and recent months use complete months only.
How does December in Williamsport compare across Pennsylvania?
Across the 108 places PlainClimate covers in Pennsylvania, December normal highs run from 34°F in Laporte to 48°F in Marcus Hook; Williamsport's is 40°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.
Other months and places
- Williamsport in November51°F by day, 33°F at night
- Williamsport in January35°F by day, 20°F at night
- Williamsport through the yearEvery month, frost dates, records and recent years
- Pennsylvania in DecemberThe statewide normal and the warmest and coolest places
- Marcus Hook: Pennsylvania's warmest Decembernormal high 48°F