How Crowded Is Frederick Law Olmsted National Historic Site in September?

September runs about 1.8× Frederick Law Olmsted National Historic Site's average month, which makes it a very busy month here — roughly 15% of the park's yearly visitors come in September.

In a typical September the park sees roughly 1,300 recreation visits, based on National Park Service monthly counts from 1981 to 2025.

That makes September the 2nd-busiest of the park's twelve months, sitting between the July peak (1.8×) and the January low (0.2×).

On our Best Time to Visit score September rates 46/100 ("Fair"), versus the top-rated May at 63/100 — pleasant weather with noticeably thinner crowds (shoulder season).

Typical September weather, from 1991–2020 NOAA climate normals at the nearest station, averages a daytime high near 76°F and an overnight low around 55°F, with about 4" of precipitation.

That average of about 65°F is a comfortable range for hiking and being outdoors all day.

Because June, July and August together draw about 39% 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 12.3 hours of daylight in September to explore — between the 8.9-hour midwinter low and the 15.1-hour summer high.

Park-wide, 2025 drew 7,240 recreation visits, down 45.2% from 13,218 in 2024.

Across the past decade overall visitation has risen about 25.3%, so a September visit is likely to feel busier than it did a few years ago.