Best time to visit Glacier.

Crowd score

Formula: 100 − (this month's visits ÷ park's peak month visits) × 100. Each park scored against its own peak, not against other parks.

Source: NPS Visitor Use Statistics Data Package 2025, Recreation Visits (TRV), 5-year monthly mean (2021-2025). Reproduce these numbers on the NPS IRMA Stats portal.

Reading it: July at Glacier reads 0 (peak). February reads 98 (quietest). A 50 means about half the park's peak crowd.

Weather score

Formula: weatherScore = round(max(0, min(100, dayComfort − precipPenalty − snowPenalty − freezePenalty))). The piecewise day-comfort function is continuous at every boundary.

• Day comfort: tmax < 50°F → max(10, (tmax − 20) × 2) (cold tail); 50–60°F → 60 + (tmax − 50) × 4 (ramp to 100); 60–78°F → 100 (plateau); 78–85°F → 100 − (tmax − 78) × 5 (ramp to 65); > 85°F → max(30, 65 − (tmax − 85) × 5) (hot tail).
• Precip penalty: max(0, prcpIn − 1.5) × 8; kicks in above 1.5 in / month.
• Snow penalty: snowIn × 2.5. If the selected station does not publish a snowfall normal, the score applies no snow penalty and labels snowfall as unavailable.
• Night-freeze penalty: max(0, 32 − tmin) × 1.5 when tmin < 32°F.

Source: NOAA NCEI U.S. Climate Normals 1991-2020, station W Glacier, MT (USC00248809, 3,148 ft).

Caveat: The W Glacier station sits near the West Entrance at about 3,148 ft, in the valley where the plowed winter road starts. The east side (St. Mary, Many Glacier, Two Medicine) and Logan Pass, at 6,646 ft, are higher, so expect colder weather there. Treat these numbers as a west-side valley guide; high-country hikes need a mountain forecast.

Access score

Formula: For each named park road, count it open if its typical operating window covers that month. Score = round((sum of weights of open roads / sum of all weights) x 100). Where a park has a partial winter access mode, the profile documents that assumption in its access notes.

Route weights at Glacier:

• Going-to-the-Sun Road (full traverse over Logan Pass): Full traverse typically late Jun/early Jul → third Mon in Oct
• Many Glacier Road: Typically late May → third weekend in November
• Two Medicine Road: Typically late May → once snow requires it
• No vehicle reservations in 2026: 2026 · no vehicle reservation
• Entry, fees, and timed entry: Year-round entry
• Lodging: Summer only · mid-May → early Oct, by lodge
• Wildlife and bear safety: Year-round · peaks summer

Editorial methodology: the route weights are chosen by our editors from NPS road and lodge operating dates and the park's own access caveats below the score table.

Caveat: The score reflects wheeled-vehicle road access only. Backcountry, hiking, lodging, shuttle, and other service availability are not directly included unless the park profile states otherwise.

Why no combined score?

A combined "best month" number forces a weighting: how much do you care about crowds vs. weather vs. access? Those weights are personal. A photographer optimizing for golden light weights differently than a parent locked to school break weights differently than a winter visitor with a 4WD. We show the inputs and let you decide. Use the per-month grid above to navigate to a deeper page.