Best Time to Visit San Juan

San Juan National Historic Site is a National Historic Site in PR and a moderately visited park, drawing about 1.4 million recreation visits in 2025. Visitation has climbed over the past decade, up roughly 7.7%, so crowds are trending heavier each year. Crowds concentrate sharply by season: March is the busiest month at about 1.4× the park's average month, while September is the calmest at roughly 0.5× — a 3-to-1 swing between high and low season. Roughly 27% of the year's visitors arrive in the three summer months of June, July and August alone, so timing a trip outside that window is the single biggest lever on how crowded the park feels. If avoiding people matters most, September offers the thinnest crowds of the year, though you'll trade some warmth and daylight for the solitude. Daylight ranges from about 10.9 hours in midwinter to 13.1 hours near the summer solstice, which shapes how much ground you can cover in a day. A standard private-vehicle entrance pass runs about $10, valid for several days, so a shoulder-season trip stretches that fee across quieter, more comfortable days. These crowd figures are drawn from 1979–2025 of National Park Service visitor-use records, and are updated as new monthly data is released.