Boise, United States — Weather in January 2027

Monthly climate averages for Boise, United States. Based on 10-year ERA5 reanalysis data.

Csa Hot-Summer Mediterranean
1.8 /10
Poor

January is a poor month in Boise

Climate Overview

Boise, United States in January has cold conditions, with highs averaging around 4.4°C (40°F). Rain falls on about 10 days this month.

This month falls at the middle of Winter. Cold conditions dominate the month.

Daily highs in January gradually rise from around 3°C (38°F) at the start to 6°C (42°F) by month's end.

Rainfall is heaviest during the first third of the month, while the last third tends to be drier.

Expect around 5.9h of sunshine at the start of January, increasing to 7.2h by the end.

The warmest days tend to fall around the 30th, averaging 5.9°C (43°F).

Temperatures will rise further into February.

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Monthly January Averages

Temperature
4°C / -4°C
Feels Like
1°C / -8°C
Rain
10 days · 46 mm
Sunshine
6.5h / day
Humidity
75% — Humid
Wind
18 km/h
Wind Direction
E (83°)
Gusts
34 km/h
Daylight
9.4 h
Cloud Cover
62%
Clear Sky Days
3.6
UV Index
2.2 — Moderate
Dew Point
-4°C — Dry
Moon Phase
First Quarter · 46%
Snow Days
8 days · 12.9 cm
Frost Days
24 days

Climate Charts

Daily averages based on historical data (2016–2025)

Daily Temperature

12°C 8°C 4°C 0°C -4°C -8°C -12°C 151015202531
High Low

Daily Precipitation

0 mm 2 mm 4 mm 6 mm 151015202531
Rainfall

Daily Sunshine

0h 2h 4h 6h 8h 10h 151015202531
Sunshine

Daily Wind Speed

0 5 10 15 20 25 151015202531
Wind Speed
Sun Position
Sunrise 08:15
Daylight 9.3h
Sunset 17:34

What to Expect

Cold daytime highs of 4°C (40°F) mean shorter outdoor excursions with warming breaks.

Rain usually comes in shorter passing showers rather than all-day rain.

1 of the last 5 yearly records were warmer than this month's long-run average.

Compare Months

January
Poor
Temp
4°C / -4°C
Feels Like
1°C / -8°C
Rain
10days (46 mm) Wet
Sun
6.5h Fair
Humidity
75% Muggy
UV
2.2 Moderate
Snow Days
8days
View Details
February
Poor
Temp
7°C / -2°C
Feels Like
3°C / -6°C
Rain
9days (41 mm) Wet
Sun
7.5h Good
Humidity
69% Muggy
UV
3.1 Moderate
Snow Days
8days
View Details
March
Fair
Temp
13°C / 1°C
Feels Like
9°C / -3°C
Rain
10days (40 mm) Wet
Sun
9.4h Good
Humidity
63% Muggy
UV
4.7 Moderate
Snow Days
4days
View Details
April
Fair
Temp
18°C / 4°C
Feels Like
14°C / 1°C
Rain
6days (31 mm) Good
Sun
11h Excellent
Humidity
54% Moderate
UV
6.3 High
Snow Days
1days
View Details
May
Good
Temp
23°C / 9°C
Feels Like
21°C / 6°C
Rain
7days (34 mm) Good
Sun
12.4h Excellent
Humidity
51% Moderate
UV
7.2 Very High
View Details
June best
Excellent
Temp
29°C / 14°C
Feels Like
27°C / 12°C
Rain
3days (16 mm) Excellent
Sun
13.4h Excellent
Humidity
41% Moderate
UV
7.7 Very High
View Details
July best
Excellent
Temp
35°C / 19°C
Feels Like
33°C / 18°C
Rain
1days (2 mm) Excellent
Sun
13.8h Excellent
Humidity
29% Comfortable
UV
7.8 Very High
View Details
August best
Excellent
Temp
33°C / 18°C
Feels Like
32°C / 17°C
Rain
1days (8 mm) Excellent
Sun
12.5h Excellent
Humidity
33% Comfortable
UV
7 High
View Details
September best
Excellent
Temp
28°C / 14°C
Feels Like
25°C / 12°C
Rain
2days (9 mm) Excellent
Sun
11h Excellent
Humidity
41% Moderate
UV
5.8 High
View Details
October
Good
Temp
19°C / 7°C
Feels Like
15°C / 4°C
Rain
5days (26 mm) Good
Sun
9h Good
Humidity
54% Moderate
UV
4.2 Moderate
View Details
November
Poor
Temp
11°C / 2°C
Feels Like
7°C / -2°C
Rain
6days (30 mm) Good
Sun
7.2h Good
Humidity
67% Muggy
UV
2.5 Moderate
Snow Days
2days
View Details
December
Poor
Temp
5°C / -3°C
Feels Like
1°C / -7°C
Rain
10days (51 mm) Wet
Sun
5.8h Fair
Humidity
75% Muggy
UV
1.8 Low
Snow Days
8days
View Details
Month Temp Feels Like Rain Sun Humidity UV Status
January 4°C / -4°C 1°C / -8°C 10days (46 mm) Wet 6.5h Fair 75% Muggy 2.2 Moderate Poor View Details
February 7°C / -2°C 3°C / -6°C 9days (41 mm) Wet 7.5h Good 69% Muggy 3.1 Moderate Poor View Details
March 13°C / 1°C 9°C / -3°C 10days (40 mm) Wet 9.4h Good 63% Muggy 4.7 Moderate Fair View Details
April 18°C / 4°C 14°C / 1°C 6days (31 mm) Good 11h Excellent 54% Moderate 6.3 High Fair View Details
May 23°C / 9°C 21°C / 6°C 7days (34 mm) Good 12.4h Excellent 51% Moderate 7.2 Very High Good View Details
June best 29°C / 14°C 27°C / 12°C 3days (16 mm) Excellent 13.4h Excellent 41% Moderate 7.7 Very High Excellent View Details
July best 35°C / 19°C 33°C / 18°C 1days (2 mm) Excellent 13.8h Excellent 29% Comfortable 7.8 Very High Excellent View Details
August best 33°C / 18°C 32°C / 17°C 1days (8 mm) Excellent 12.5h Excellent 33% Comfortable 7 High Excellent View Details
September best 28°C / 14°C 25°C / 12°C 2days (9 mm) Excellent 11h Excellent 41% Moderate 5.8 High Excellent View Details
October 19°C / 7°C 15°C / 4°C 5days (26 mm) Good 9h Good 54% Moderate 4.2 Moderate Good View Details
November 11°C / 2°C 7°C / -2°C 6days (30 mm) Good 7.2h Good 67% Muggy 2.5 Moderate Poor View Details
December 5°C / -3°C 1°C / -7°C 10days (51 mm) Wet 5.8h Fair 75% Muggy 1.8 Low Poor View Details

What to Wear

Full winter gear is a must — insulated coat, thermal base layers, warm hat, gloves, and waterproof boots.

A waterproof jacket or compact umbrella is recommended for occasional showers.

Packing List

Warm coatThermal base layersScarf & glovesUmbrellaWaterproof jacketComfortable walking shoes

Frequently Asked Questions

January is typically poor for visiting Boise, with average highs of 4°C (40°F) and around 10 rainy days. Boise, United States in January has cold conditions, with highs averaging around 4.4°C (40°F). Rain falls on about 10 da
Boise typically sees around 10 rainy days in January with 46 mm (1.8 in) of total rainfall. An umbrella should suffice.
Yes, nights in Boise during January are cold, averaging -4°C (25°F). Pack warm layers and a coat for evenings.
With highs of 4°C (40°F) and lows of -4°C (25°F) in January, we recommend: Warm coat, Thermal base layers, Scarf & gloves, Umbrella, Waterproof jacket. Comfortable walking shoes are essential.
January is not the most favourable month weather-wise in Boise. Consider visiting during months with milder temperatures or less rainfall for a better experience.
The average UV index in Boise during January is 2 (low). No special sun protection is needed.
Boise gets approximately 9 hours of daylight per day in January, with around 7 hours of sunshine.
Yes, Boise typically sees around 8 snow days in January with roughly 13 cm (5 in) of snowfall.

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