How Crowded Is Castillo de San Marcos in August?
August is a quiet month at Castillo de San Marcos National Monument, running about 0.8× the park's average month — roughly 6% of the year's visitors come in August. That puts it between the March peak and the September low. Overall our best-time score rates August as "Good" for a visit. Typical August weather averages a high near 90°F and a low around 74°F, with about 7.2" of precipitation. You'll get about 13.1 hours of daylight to explore.
Frequently Asked Questions
August is quiet at Castillo de San Marcos National Monument (about 0.8× the average month). Our best-time score rates it "Good". The single best month overall is October.
The busiest month is March and the quietest is September. August sits at about 0.8× the park's average, or 6% of annual visitation.
Source: National Park Service Visitor Use Statistics (1979–2025), NOAA NCEI Climate Normals 1991–2020. Updated 2026-06-20.