Boise weather in December

Locals call December here touch and go, which is arithmetic rather than pessimism: Bald Mountain opens on Thanksgiving on a great deal of snowmaking and is usually running top to bottom by then, so the lifts are a safer bet than the snow. Early-December trips have had terrific conditions. Late December has also, in plenty of years, been short of enough natural cover for the cross-country at Galena, and two long-time residents on the forum disagree about how often that happens. Galena Lodge is the fallback when the downhill is thin, for nordic skiing and snowshoeing. The record: 0.2C days that feel like -3C, -12.4C nights, 66.1cm of snow, 8.6 precipitation days and only 6.2 hours of sun.

Forum posters describe March in Boise as genuinely transitional - it could feel like winter or like spring, sometimes both within the same day. Posters citing a mid-March spring break stretch reported daytime highs typically in the low 60sF with nighttime lows in the 30sF, alongside spring flowers and greenery starting to appear. Posters discussing wintry conditions that occasionally linger into late February or early March are consistent that any snow or cold snap this late in the season tends to resolve within a day or two rather than sticking around. Posters generally rate March as a genuinely mixed early-spring month for Boise, mild afternoons and chilly mornings the reliable pattern, with real day-to-day variability still worth planning around.

Forum regulars consistently pick September as prime time: mid-month temperatures run about 10 degrees cooler than late August (roughly 65F vs 75F), so you still get long warm days and comfortable nights without August's peak heat and fire risk. One poster's blunt reasoning: it's hot in August with a real chance of wildfire smoke, so September is when 'most tourists are gone and locals have their place back' - you also land right in the run of outdoor events like Jazz on the Grove and the weekly Alive After Five series. Worth a heads-up regardless: wildland fire smoke is possible in September, not guaranteed, but common enough that forum regulars flag it every year.