How Crowded Is Manhattan Project National Historical Park in July?

July runs about 1.7× Manhattan Project National Historical Park's average month, which makes it a very busy month here — roughly 14% of the park's yearly visitors come in July.

In a typical July the park sees roughly 9,000 recreation visits, based on National Park Service monthly counts from 2016 to 2025.

It is the single busiest month of the year at Manhattan Project; January, the quietest, runs only about 0.3× the average — a 6-to-1 swing between high and low season.

On our Best Time to Visit score July rates 51/100 ("Fair"), versus the top-rated May at 56/100 — pleasant weather with noticeably thinner crowds (shoulder season).

Typical July weather, from 1991–2020 NOAA climate normals at the nearest station, averages a daytime high near 83°F and an overnight low around 57°F, with about 2.9" of precipitation.

That average of about 70°F is a comfortable range for hiking and being outdoors all day.

July falls inside the park's busiest stretch: June, July and August together pull about 37% of the year's visitors, so a visit this month means sharing the park with the peak-season crowd.

You'll have about 14.2 hours of daylight in July to explore — near the year-round maximum.

Park-wide, 2025 drew 56,390 recreation visits, down 24.5% from 74,693 in 2024.

Across the past decade overall visitation has eased about 43.1%, so July may feel a touch quieter than it once did.