How Crowded Is Castillo de San Marcos National Monument in March?

March runs about 1.5× Castillo de San Marcos National Monument's average month, which makes it a busy month here — roughly 13% of the park's yearly visitors come in March.

In a typical March the park sees about 80,000 recreation visits, based on National Park Service monthly counts from 1979 to 2025.

It is the single busiest month of the year at Castillo de San Marcos; September, the quietest, runs only about 0.6× the average — a 3-to-1 swing between high and low season.

On our Best Time to Visit score March rates 43/100 ("Poor"), versus the top-rated October at 77/100 — pleasant weather with noticeably thinner crowds (shoulder season).

Typical March weather, from 1991–2020 NOAA climate normals at the nearest station, averages a daytime high near 74°F and an overnight low around 55°F, with about 3.4" 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 24% of annual visitors, choosing March instead steps outside that summer crush — the single biggest lever on how crowded the park feels.

You'll have about 11.8 hours of daylight in March to explore — between the 10.1-hour midwinter low and the 13.9-hour summer high.

Park-wide, 2025 drew 598,070 recreation visits, up 3.1% from 579,825 in 2024.

Across the past decade overall visitation has eased about 13.4%, so March may feel a touch quieter than it once did.