Boise
Idaho, USA
Long-term weather forecast
Long-term weather forecast

December weather forecast and climate
Boise, ID

The golden fall season in Boise, Idaho, with the tall city buildings
The golden fall season in Boise, Idaho, with the tall city buildings
The first month of the winter, December, is still a cold month in Boise, Idaho, with average temperature fluctuating between 37.6°F (3.1°C) and 24.1°F (-4.4°C).

Temperature

With an average high-temperature of 37.6°F (3.1°C) and an average low-temperature of 24.1°F (-4.4°C), December is the coldest month.

Humidity

The average relative humidity in December is 74.6%.

Rainfall

The month with the most rainfall is December when the rain falls for 11.8 days and typically aggregates up to 1.6" (39.4mm) of precipitation.

Snowfall

January through April, October through December are months with snowfall in Boise. The month with the most snowfall is December when snow falls for 6 days and typically aggregates up to 7" (177.8mm) of snow.

Daylight

With an average of 9h of daylight, December has the shortest days of the year in Boise.

Sunshine

The month with the least sunshine is December, with an average of 3.4h of sunshine.

UV index

Months with the lowest UV index are January and December, with an average maximum UV index of 1. A UV Index reading of 2, and below, represents a minimal health hazard from unsafe exposure to the UV radiation for the average person.
In December, the average maximum UV index of 1 translate into the following recommendations:
Most people can stay in the Sun for up to 1 hour without burning, apart from children that always must be protected from sun exposure. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.

What is the coldest month in Boise?

December is the coldest month, with an average high-temperature of 37.6°F (3.1°C) and an average low-temperature of 24.1°F (-4.4°C).

What is the temperature in December in Boise?

In Boise, in December, the average high-temperature is 37.6°F (3.1°C), and the average low-temperature is 24.1°F (-4.4°C).

What is the average humidity in December in Boise?

The average relative humidity in December is 74.6%.

How much does it rain in Boise in December?

In Boise, in December, during 11.8 rainfall days, 1.6" (39.4mm) of precipitation is typically accumulated.

What is the rainiest month in Boise?

December is the month with the most rainfall in Boise, Idaho. Rain falls for 11.8 days and accumulates 1.6" (39.4mm) of precipitation.

How many days does it snow in December in Boise?

In Boise, in December, snow falls for 6 days, with typically accumulated 7" (177.8mm) of snow.

What is the snowiest month in Boise?

The month with the most snowfall in Boise is December when snow falls for 6 days and typically aggregates up to 7" (177.8mm) of snow.

What is the month with the shortest days in Boise?

The month with the shortest days in Boise, Idaho, is December, with an average of 9h of daylight.

What is the average length of the day in December in Boise?

In Boise, Idaho, the average length of the day in December is 9h.

What is the month with the least sunshine in Boise?

December has the least sunshine of the year in Boise, Idaho, with an average of 3.4h of sunshine.

How long on average sun shines in December in Boise?

The average sunshine in December in Boise, Idaho, is 3.4h.

When is the lowest UV index in Boise?

January and December, with an average maximum UV index of 1, are months with the lowest UV index.

How high is the UV index in December in Boise?

In December, the average daily maximum UV index is 1. A UV Index value of 2, and less, symbolizes a low health risk from the exposure to the Sun's UV radiation.
Average temperature in December - Boise, ID
  • Average high temperature in December: 37.5°F

The warmest month (with the highest average high temperature) is July (91.2°F).
The month with the lowest average high temperature is December (37.5°F).

  • Average low temperature in December: 24°F

The month with the highest average low temperature is July (60.4°F).
The coldest month (with the lowest average low temperature) is December (24°F).

Average humidity in December - Boise, ID
  • Average humidity in December: 74.6%

The month with the highest relative humidity is January (75%).
The month with the lowest relative humidity is July (36.1%).

Average rainfall in December - Boise, ID
  • Average rainfall in December: 1.6"

The wettest month (with the highest rainfall) is December (1.6").
The driest month (with the lowest rainfall) is August (0.2").

Average rainfall days in December - Boise, ID
  • Average rainfall days in December: 11.8 days

The month with the highest number of rainy days is December (11.8 days).
The month with the lowest number of rainy days is August (2.4 days).

Average snowfall in December - Boise, ID
  • Average snowfall in December: 7"

The month with the highest snowfall is December (7").
Months with the lowest snowfall are May, June, July, August and September (0").

Average snowfall days in December - Boise, ID
  • Average snowfall days in December: 6 days

The month with the highest number of snowfall days is December (6 days).
Months with the lowest number of snowfall days are May, June, July, August and September (0 days).

Average daylight in December / Average sunshine in December - Boise, ID
  • Average daylight in December: 9h

The month with the longest days is June (Average daylight: 15.4h).
The month with shortest days is December (Average daylight: 9h).

  • Average sunshine in December: 3.4h

The month with most sunshine is July (Average sunshine: 12.9h).
The month with least sunshine is December (Average sunshine: 3.4h).

Average UV index in December - Boise, ID
  • Average UV index in December: 1

Months with the highest UV index are June and July (UV index 9).
Months with the lowest UV index are January and December (UV index 1).