Boston weather in December: Boston, Massachusetts: normal highs, lows, rain and records for December
Boston in December has a normal high of 42°F and a normal low of 29°F, a daily mean of 36°F, falling from 46°F on the 1st to 39°F by the 31st. Measurable precipitation falls on 12 days in a normal December, 4.30 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 6°C and low of −2°C, 109 mm of precipitation and 23 cm of snow in December.
- NOAA stationBoston Logan International Airport
- Station IDUSW00014739
- Location42.36°N 71.01°W
- Elevation12 ft (4 m)
- From the center2 miles
- Population673,458
- Jan 37° 23°
- Feb 39° 25°
- Mar 46° 31°
- Apr 56° 41°
- May 67° 50°
- Jun 76° 60°
- Jul 82° 66°
- Aug 80° 65°
- Sep 73° 58°
- Oct 62° 48°
- Nov 52° 38°
- Dec 42° 29°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Boston in December?
The normal high is 42°F and the normal low 29°F, for a daily mean of 35.7°F. December is 9.0°F cooler than November and 5.8°F warmer than January. December is the 10th warmest month of the year in Boston and the wettest. Across the month the normal high falls 7°F, from 46°F on December 1 to 39°F on December 31. From one year to the next December's mean temperature typically moves about 3.5°F either way (NOAA's standard deviation), so roughly two Decembers in three average between 32°F and 39°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 | 46°F | 33°F | 36% | 23% |
| December 8 | 44°F | 31°F | 37% | 23% |
| December 15 | 42°F | 29°F | 38% | 23% |
| December 22 | 41°F | 28°F | 39% | 23% |
| December 31 | 39°F | 25°F | 39% | 23% |
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 | 46°F | 33°F | 36% | 23% | 9 h 20 min |
| December 2 | 46°F | 33°F | 37% | 23% | 9 h 20 min |
| December 3 | 46°F | 33°F | 37% | 23% | 9 h 20 min |
| December 4 | 46°F | 32°F | 37% | 23% | 9 h 20 min |
| December 5 | 45°F | 32°F | 37% | 23% | 9 h 20 min |
| December 6 | 45°F | 32°F | 37% | 23% | 9 h 10 min |
| December 7 | 45°F | 32°F | 37% | 23% | 9 h 10 min |
| December 8 | 44°F | 31°F | 37% | 23% | 9 h 10 min |
| December 9 | 44°F | 31°F | 37% | 23% | 9 h 10 min |
| December 10 | 44°F | 31°F | 38% | 23% | 9 h 10 min |
| December 11 | 43°F | 31°F | 38% | 23% | 9 h 10 min |
| December 12 | 43°F | 30°F | 38% | 23% | 9 h 10 min |
| December 13 | 43°F | 30°F | 38% | 23% | 9 h 10 min |
| December 14 | 43°F | 30°F | 38% | 23% | 9 h 10 min |
| December 15 | 42°F | 29°F | 38% | 23% | 9 h 10 min |
| December 16 | 42°F | 29°F | 38% | 23% | 9 h 10 min |
| December 17 | 42°F | 29°F | 38% | 23% | 9 h 10 min |
| December 18 | 42°F | 29°F | 38% | 23% | 9 h 10 min |
| December 19 | 41°F | 28°F | 38% | 23% | 9 h |
| December 20 | 41°F | 28°F | 38% | 23% | 9 h |
| December 21 | 41°F | 28°F | 38% | 23% | 9 h |
| December 22 | 41°F | 28°F | 39% | 23% | 9 h |
| December 23 | 40°F | 27°F | 39% | 23% | 9 h |
| December 24 | 40°F | 27°F | 39% | 23% | 9 h |
| December 25 | 40°F | 27°F | 39% | 23% | 9 h |
| December 26 | 40°F | 27°F | 39% | 23% | 9 h |
| December 27 | 39°F | 26°F | 39% | 23% | 9 h 10 min |
| December 28 | 39°F | 26°F | 39% | 23% | 9 h 10 min |
| December 29 | 39°F | 26°F | 39% | 23% | 9 h 10 min |
| December 30 | 39°F | 26°F | 39% | 23% | 9 h 10 min |
| December 31 | 39°F | 25°F | 39% | 23% | 9 h 10 min |
- Normal high
- 42°FDecember average
- Normal low
- 29°FDecember average
- Precipitation
- 4.30 inmonth total
- Days with precipitation
- 120.01 inch or more
- Snowfall
- 9.0 inmonth total
- Nights at 32°F or colder
- 20
- 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 USW00014739; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain or snow in Boston in December?
On a given December day the chance of 0.01 inch or more is 38% on average, highest around December 29 (39%). In all, 4.30 in falls on 12 days of a normal December, 1 of them with an inch or more.
In a normal December in Boston, 20 nights fall to freezing, 4 days stay below freezing all day and snowfall averages 9.0 inches.
Snow falls on 4 days in a normal December.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00014739.
How humid and windy is Boston in December?
At 3 p.m. the normal temperature is 37°F with 53% relative humidity and a dew point of 21°F; at 6 a.m. it is 30°F with 68% humidity. The wind averages 12.3 mph, most often from the west-northwest in the afternoon. A dew point under 50°F feels dry.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 30°F | 21°F | 68% | 11.9 mph | 42% |
| 9 a.m. | 32°F | 21°F | 65% | 12.3 mph | 30% |
| noon | 36°F | 22°F | 56% | 13.0 mph | 28% |
| 3 p.m. | 37°F | 21°F | 53% | 13.1 mph | 24% |
| 6 p.m. | 34°F | 21°F | 58% | 12.1 mph | 38% |
| 9 p.m. | 33°F | 21°F | 62% | 12.4 mph | 42% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00014739. 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 Boston?
The warmest December temperature on Boston's official record (since 1872) is 76°F, on December 7, 1998; the coldest is −17°F, on December 29, 1933. The wettest December brought 9.74 in (1969); the snowiest, 27.9 inches (1970).
The December mean against the 1991-2020 normal of 35.7°F: 2021 39.2°F (+3.5), 2022 37.3°F (+1.6), 2023 40.8°F (+5.1), 2024 35.3°F (−0.4), 2025 31.3°F (−4.4). 3 of 5 ran warmer than normal.
| December | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 39.2°F | +3.5°F | 2.45 in |
| 2022 | 37.3°F | +1.6°F | 3.75 in |
| 2023 | 40.8°F | +5.1°F | 6.10 in |
| 2024 | 35.3°F | −0.4°F | 5.65 in |
| 2025 | 31.3°F | −4.4°F | 2.39 in |
Source: records: ACIS, NWS threaded record BOSthr; recent months: ACIS, station USW00014739. Records and recent months use complete months only.
How does December in Boston compare across Massachusetts?
Across the 35 places PlainClimate covers in Massachusetts, December normal highs run from 36°F in Pittsfield to 46°F in Edgartown; Boston's is 42°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.