How Crowded Is Castillo de San Marcos in March?
March is a busy month at Castillo de San Marcos National Monument, running about 1.5× the park's average month — roughly 13% of the year's visitors come in March. It is in fact the busiest month of the year here, so expect full parking lots, busy trails and booked-out campgrounds. If crowds bother you, September (the quietest month) or the recommended October are easier. Typical March weather averages a high near 74°F and a low around 55°F, with about 3.4" of precipitation. You'll get about 11.8 hours of daylight to explore.
Frequently Asked Questions
March is busy at Castillo de San Marcos National Monument (about 1.5× the average month). Our best-time score rates it "Poor". The single best month overall is October.
The busiest month is March and the quietest is September. March sits at about 1.5× the park's average, or 13% of annual visitation.
Source: National Park Service Visitor Use Statistics (1979–2025), NOAA NCEI Climate Normals 1991–2020. Updated 2026-06-20.