How Crowded Is Manhattan Project in May?
May is a busy month at Manhattan Project National Historical Park, running about 1.2× the park's average month — roughly 10% of the year's visitors come in May. That puts it between the July peak and the January low. Overall our best-time score rates May as "Fair" for a visit. Typical May weather averages a high near 70°F and a low around 44°F, with about 1.2" of precipitation. You'll get about 13.9 hours of daylight to explore.
Frequently Asked Questions
May is busy at Manhattan Project National Historical Park (about 1.2× the average month). Our best-time score rates it "Fair". The single best month overall is May.
The busiest month is July and the quietest is January. May sits at about 1.2× the park's average, or 10% of annual visitation.
Source: National Park Service Visitor Use Statistics (2016–2025), NOAA NCEI Climate Normals 1991–2020. Updated 2026-06-20.