Boise · December
Run in the midday.
Cold: average high 39°F, low 25°F. Layering becomes the workout. Cold mornings warm into runnable midday hours — the windows around noon catch the warmest temperatures.
Avg high / low
39° / 25°F
Humidity
74%
Rain days
14/mo
Wind
11 mph
What December feels like in Boise
Sunrise
09:10
Mid-month average
Sunset
18:11
Mid-month average
Time-of-day breakdown
Morning
Coolest, driest air of the day. The window before sunrise is the most reliable comfortable hour.
Midday
Often the warmest few hours of a cold day. If you can only run once, midday gives you the most temperate window.
Evening
Cold drops back in fast after sunset. Tight window — done before headlamp territory.
What to wear running in Boise in December
The kit for December in Boise: cold-weather layers, gloves, and ear coverage on most mornings, a water-resistant cap or jacket on standby.
December vs the surrounding months
vs November
-10° avg high
+4 rain days
Boise in November →
December
39°F avg high
14 rain days
Best: midday
vs January
-1° avg high
+2 rain days
Boise in January →
Frequently Asked Questions
What is the best time of day to run in Boise in December?+
Midday. Cold mornings warm into runnable midday hours — the windows around noon catch the warmest temperatures.
What's the average temperature in Boise in December?+
Average high 39°F, average low 25°F.
How does December compare to surrounding months in Boise?+
Compared to November (avg high 49°F), December is cooler. Compared to January (avg high 40°F), December is cooler.
Does it rain often in Boise in December?+
Expect about 14 measurable rain days in December, on average.