How Crowded Is Manhattan Project National Historical Park in April?

April runs about 1.1× Manhattan Project National Historical Park's average month, which makes it an average month here — roughly 9% of the park's yearly visitors come in April.

In a typical April the park sees roughly 5,800 recreation visits, based on National Park Service monthly counts from 2016 to 2025.

That makes April the 7th-busiest of the park's twelve months, sitting between the July peak (1.7×) and the January low (0.3×).

On our Best Time to Visit score April rates 42/100 ("Poor"), versus the top-rated May at 56/100 — pleasant weather with noticeably thinner crowds (shoulder season).

Typical April weather, from 1991–2020 NOAA climate normals at the nearest station, averages a daytime high near 61°F and an overnight low around 35°F, with about 0.9" of precipitation and roughly 3" of snow.

That average of about 48°F is cool, so layers and a shorter daylight window matter.

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

You'll have about 12.9 hours of daylight in April to explore — between the 9.6-hour midwinter low and the 14.4-hour summer high.

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 April may feel a touch quieter than it once did.