How Crowded Is Fort Union National Monument in September?

September runs about 1.2× Fort Union National Monument's average month, which makes it a busy month here — roughly 10% of the park's yearly visitors come in September.

In a typical September the park sees roughly 1,000 recreation visits, based on National Park Service monthly counts from 1979 to 2025.

That makes September the 5th-busiest of the park's twelve months, sitting between the June peak (1.7×) and the January low (0.3×).

On our Best Time to Visit score September rates 57/100 ("Fair"), versus the top-rated August at 65/100 — best overall balance of crowds, weather and daylight.

Typical September weather, from 1991–2020 NOAA climate normals at the nearest station, averages a daytime high near 80°F and an overnight low around 43°F, with about 2.1" of precipitation.

That average of about 62°F is a comfortable range for hiking and being outdoors all day.

Because June, July and August together draw about 37% of annual visitors, choosing September instead steps outside that summer crush — the single biggest lever on how crowded the park feels.

You'll have about 12.2 hours of daylight in September to explore — between the 9.6-hour midwinter low and the 14.4-hour summer high.

Park-wide, 2024 drew 9,217 recreation visits, down 3.7% from 9,570 in 2023.

Across the past decade overall visitation has eased about 12.5%, so September may feel a touch quieter than it once did.