Boise weather in December: Boise, Idaho: normal highs, lows, rain and records for December
Boise in December has a normal high of 39°F and a normal low of 25°F, a daily mean of 32°F, falling from 42°F on the 1st to 37°F by the 31st. Measurable precipitation falls on 12 days in a normal December, 1.54 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 4°C and low of −4°C, 39 mm of precipitation and 14 cm of snow in December.
- NOAA stationBoise Air Terminal
- Station IDUSW00024131
- Location43.57°N 116.24°W
- Elevation2,814 ft (858 m)
- From the center2 miles
- Population237,963
- Jan 39° 26°
- Feb 46° 29°
- Mar 56° 35°
- Apr 62° 40°
- May 72° 48°
- Jun 81° 54°
- Jul 93° 62°
- Aug 91° 61°
- Sep 80° 53°
- Oct 65° 42°
- Nov 49° 32°
- Dec 39° 25°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Boise in December?
The normal high is 39°F and the normal low 25°F, for a daily mean of 32.1°F. December is 8.2°F cooler than November and 0.1°F cooler than January. December is the 12th warmest month of the year in Boise and the wettest, and the snowiest. Across the month the normal high falls 5°F, from 42°F on December 1 to 37°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 29°F and 36°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 38%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| December 1 | 42°F | 28°F | 36% | 15% |
| December 8 | 40°F | 26°F | 37% | 15% |
| December 15 | 38°F | 25°F | 38% | 15% |
| December 22 | 38°F | 25°F | 38% | 15% |
| December 31 | 37°F | 24°F | 38% | 15% |
Every day of December: normal high, low and chance of precipitation (warmest afternoon December 1, coldest night December 26)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| December 1 | 42°F | 28°F | 36% | 15% | 9 h 10 min |
| December 2 | 42°F | 28°F | 36% | 15% | 9 h 10 min |
| December 3 | 41°F | 27°F | 36% | 15% | 9 h 10 min |
| December 4 | 41°F | 27°F | 37% | 15% | 9 h 10 min |
| December 5 | 41°F | 27°F | 37% | 15% | 9 h 10 min |
| December 6 | 41°F | 27°F | 37% | 15% | 9 h 10 min |
| December 7 | 40°F | 27°F | 37% | 15% | 9 h |
| December 8 | 40°F | 26°F | 37% | 15% | 9 h |
| December 9 | 40°F | 26°F | 37% | 15% | 9 h |
| December 10 | 39°F | 26°F | 37% | 15% | 9 h |
| December 11 | 39°F | 26°F | 37% | 15% | 9 h |
| December 12 | 39°F | 26°F | 37% | 15% | 9 h |
| December 13 | 39°F | 25°F | 37% | 15% | 9 h |
| December 14 | 39°F | 25°F | 38% | 15% | 9 h |
| December 15 | 38°F | 25°F | 38% | 15% | 9 h |
| December 16 | 38°F | 25°F | 38% | 15% | 9 h |
| December 17 | 38°F | 25°F | 38% | 15% | 9 h |
| December 18 | 38°F | 25°F | 38% | 15% | 9 h |
| December 19 | 38°F | 25°F | 38% | 15% | 9 h |
| December 20 | 38°F | 25°F | 38% | 15% | 9 h |
| December 21 | 38°F | 25°F | 38% | 15% | 9 h |
| December 22 | 38°F | 25°F | 38% | 15% | 9 h |
| December 23 | 38°F | 24°F | 38% | 15% | 9 h |
| December 24 | 38°F | 24°F | 38% | 15% | 9 h |
| December 25 | 37°F | 24°F | 38% | 15% | 9 h |
| December 26 | 37°F | 24°F | 38% | 15% | 9 h |
| December 27 | 37°F | 24°F | 38% | 15% | 9 h |
| December 28 | 37°F | 24°F | 38% | 15% | 9 h |
| December 29 | 37°F | 24°F | 38% | 15% | 9 h |
| December 30 | 37°F | 24°F | 38% | 15% | 9 h |
| December 31 | 37°F | 24°F | 38% | 15% | 9 h |
- Normal high
- 39°FDecember average
- Normal low
- 25°FDecember average
- Precipitation
- 1.54 inmonth total
- Days with precipitation
- 120.01 inch or more
- Snowfall
- 5.6 inmonth total
- Nights at 32°F or colder
- 25
- Daylight
- 9 h 10 min to 9 hDecember 1 to December 31
- Sunshine
- 62%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00024131; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain or snow in Boise in December?
On a given December day the chance of 0.01 inch or more is 37% on average, highest around December 22 (38%). In all, 1.54 in falls on 12 days of a normal December.
In a normal December in Boise, 25 nights fall to freezing, 7 days stay below freezing all day and snowfall averages 5.6 inches.
Snow falls on 6 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 USW00024131.
How humid and windy is Boise in December?
At 3 p.m. the normal temperature is 35°F with 65% relative humidity and a dew point of 25°F; at 6 a.m. it is 27°F with 81% humidity. The wind averages 6.6 mph, most often from the southeast 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 | 22°F | 81% | 6.1 mph | 45% |
| 9 a.m. | 27°F | 22°F | 81% | 6.2 mph | 42% |
| noon | 32°F | 24°F | 71% | 7.0 mph | 46% |
| 3 p.m. | 35°F | 25°F | 65% | 7.7 mph | 51% |
| 6 p.m. | 32°F | 24°F | 73% | 6.5 mph | 49% |
| 9 p.m. | 29°F | 23°F | 79% | 6.4 mph | 47% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00024131. 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 Boise?
The warmest December temperature on Boise's official record (since 1875) is 70°F, on December 10, 1939; the coldest is −25°F, on December 22, 1990. The wettest December brought 5.67 in (1884); the snowiest, 26.2 inches (1983).
The December mean against the 1991-2020 normal of 32.1°F: 2021 34.1°F (+2.0), 2022 29.2°F (−2.9), 2023 36.3°F (+4.2), 2024 35.7°F (+3.6), 2025 41.6°F (+9.5). 4 of 5 ran warmer than normal.
| December | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 34.1°F | +2.0°F | 1.54 in |
| 2022 | 29.2°F | −2.9°F | 2.00 in |
| 2023 | 36.3°F | +4.2°F | 1.51 in |
| 2024 | 35.7°F | +3.6°F | 2.78 in |
| 2025 | 41.6°F | +9.5°F | 2.27 in |
Source: records: ACIS, NWS threaded record BOIthr; recent months: ACIS, station USW00024131. Records and recent months use complete months only.
How does December in Boise compare across Idaho?
Across the 85 places PlainClimate covers in Idaho, December normal highs run from 26°F in Island Park to 44°F in Glenns Ferry; Boise's is 39°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.