December in Glacier National Park is a tough month: highs around 30°F, lows around 19°F. Crowds: very quiet — #7 busiest of the park's 12 months. The editorial best window here is July–September. You get about 8h 17m of daylight. To finish Grinnell Glacier (4h 25m) before dark, leave the trailhead by about 12:11 PM.
Month data reviewed · how we check this
| Verdict | Tough Closures, harsh weather or very limited access — plan carefully. |
|---|---|
| Temps °F | 30° high / 19° low |
| Crowds | very quiet · #7 busiest of the park's 12 months |
| Best window (whole year) | July–September |
| Peak crowds (whole year) | Jul–Aug |
CROWDS: RELATIVE SEASONALITY FROM NPS VISITATION STATISTICS · TEMPS: APPROXIMATE NOAA NORMALS AT MAIN VISITOR ELEVATION — HIGH COUNTRY RUNS 10–20°F COLDER
DAYLIGHT ON DECEMBER 15 · LOCAL PARK TIME (MST)COMPUTED FROM THE PARK'S OWN COORDINATES FOR THE 15TH — THE MIDDLE OF THE MONTH STANDS FOR IT, AS IT DOES FOR CLIMATE NORMALS. WITHIN A MONTH THESE TIMES SHIFT BY UP TO AN HOUR
LEAVE THE TRAILHEAD BY — TO FINISH BEFORE DARK ON DECEMBER 15WALKING TIMES ESTIMATED FROM EACH TRAIL'S MEASURED DISTANCE AND ELEVATION GAIN — A PLANNING FIGURE, NOT A PACE. ADD YOUR OWN MARGIN FOR PHOTOS, REST AND CROWDS. WATER AT THE COOL-WEATHER RATE, BECAUSE THIS MONTH AVERAGES 30°F. TRAILS WE HAVE NOT MEASURED ARE LEFT OUT RATHER THAN GUESSED
WHAT DECEMBER ASKS OF YOU HEREGlacier National Park in January — Tough, highs around 30°F, crowds: very quiet (most roads closed; quiet snowshoe country).
Our verdict for December is "Tough". Closures, harsh weather or very limited access — plan carefully. Expect highs around 30°F and lows around 19°F, with crowds at the "very quiet" level. Temperatures are approximate NOAA normals at the main visitor elevation; crowd levels follow published NPS visitation statistics.
Across the full 12-month review, the best window is July–September, and the peak-crowd months are Jul–Aug. December itself we rate "Tough".
About 8h 17m on December 15: the sun rises around 8:21 AM and sets around 4:39 PM local park time (MST). Computed from the park's own coordinates, so it is the light you actually get at the trailhead, not the nearest city's.
Grinnell Glacier takes about 4h 25m of walking, so on December 15 you would need to leave the trailhead by about 12:11 PM to finish before dark — the sun sets around 4:39 PM local park time (MST). Walking times are estimated from each trail's measured distance and elevation gain, so treat them as a planning figure and add your own margin for photos, rest and crowds.
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