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

August runs about 0.8× Castillo de San Marcos National Monument's average month, which makes it a quiet month here — roughly 6% of the park's yearly visitors come in August.

In a typical August the park sees about 41,000 recreation visits, based on National Park Service monthly counts from 1979 to 2025.

That makes August the 10th-busiest of the park's twelve months, sitting between the March peak (1.5×) and the September low (0.6×).

On our Best Time to Visit score August rates 61/100 ("Good"), versus the top-rated October at 77/100 — pleasant weather with noticeably thinner crowds (shoulder season).

Typical August weather, from 1991–2020 NOAA climate normals at the nearest station, averages a daytime high near 90°F and an overnight low around 74°F, with about 7.2" of precipitation.

That average of about 82°F is warm enough that midday heat is worth planning around.

August falls inside the park's busiest stretch: June, July and August together pull about 24% of the year's visitors, so a visit this month means sharing the park with the peak-season crowd.

You'll have about 13.1 hours of daylight in August 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 August may feel a touch quieter than it once did.