Climate averages 1991–2020
Boise weather
in January.
A cold, moderately wet month: the 11th warmest and the 11th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
January is a cold month in Boise: daytime highs average 3.8°C and nights cool to about -4.6°C. By daytime temperature it is the 11th warmest of the 12 months.
Expect about 45 mm of rain on roughly 10 days, which makes January a moderately wet month (the 11th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 9 h 20 min on an average January day.
The nearest other city in this atlas is Meridian (15 km away). In January its highs average 3.8°C, about as warm as Boise, with 40 mm of rain.
Among the 498 cities listed in the United States, Boise ranks joint 345th of 498 for the warmest January highs and joint 97th of 498 for the driest January (rainfall, lowest first). The mean January high of those 498 cities is 9.5°C; Boise is 5.6°C cooler than that mean.
From January to February, average highs rise by 3.0°C to 6.8°C, and monthly rainfall falls from 45 mm to 31 mm.
The annual picture
January in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Boise climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January, selected | 3.8°C-4.6°C | -4.6°C | 45 | 9.5 | 9.39 h |
| February | 6.8°C-2.5°C | -2.5°C | 31 | 7.7 | 10.510 h |
| March | 11.9°C0.9°C | 0.9°C | 36 | 8.9 | 11.912 h |
| April | 15.9°C3.8°C | 3.8°C | 31 | 7.2 | 13.413 h |
| May | 21.6°C8.5°C | 8.5°C | 31 | 5.9 | 14.715 h |
| June | 26.5°C13.0°C | 13.0°C | 16 | 3.2 | 15.415 h |
| July | 32.7°C17.9°C | 17.9°C | 2.6 | 0.9 | 15.115 h |
| August | 31.9°C17.4°C | 17.4°C | 3.3 | 0.7 | 14.014 h |
| September | 26.2°C12.6°C | 12.6°C | 10 | 2.2 | 12.613 h |
| October | 17.7°C6.3°C | 6.3°C | 22 | 4.3 | 11.111 h |
| November | 9.3°C0.2°C | 0.2°C | 34 | 7.9 | 9.710 h |
| December | 3.7°C-4.1°C | -4.1°C | 50 | 10.1 | 9.09 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
January in nearby cities
- Meridian in JanuaryUnited States · 15 kmHigh 3.8°C · Low -4.3°C · 40 mm rain
- Nampa in JanuaryUnited States · 30 kmHigh 4.6°C · Low -3.4°C · 40 mm rain
- Kennewick in JanuaryUnited States · 370 kmHigh 5.7°C · Low -1.7°C · 34 mm rain
- Tri-Cities in JanuaryUnited States · 376 kmHigh 6.0°C · Low -1.5°C · 34 mm rain
- Missoula in JanuaryUnited States · 401 kmHigh 0.6°C · Low -6.9°C · 45 mm precipitation
- Bend in JanuaryUnited States · 413 kmHigh 3.8°C · Low -4.7°C · 71 mm rain
- Ogden in JanuaryUnited States · 437 kmHigh 1.1°C · Low -8.1°C · 58 mm precipitation
- Layton in JanuaryUnited States · 449 kmHigh 1.2°C · Low -7.8°C · 53 mm precipitation
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Boise) is explained once on the Boise year overview and on the Sources, method and limits page.