Best Time to Visit Castillo de San Marcos National Monument
OctoberBest month to visit
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Visit Castillo de San Marcos in October
October offers pleasant weather with noticeably thinner crowds (shoulder season). For comparison, March is the most crowded month (~1.5× the average month) and September is the quietest.
Annual visits
598K
2025
Busiest month
Mar
1.5× avg
Quietest month
Sep
0.6× avg
10-yr trend
falling
-13.4%
More photos of Castillo de San Marcos
Photos courtesy of the National Park Service (public domain).
How crowded is Castillo de San Marcos by month?
Relative crowd level by month (1.0 = the park's average month), from NPS visitation records 1979–2025.
Month-by-month crowd, weather & daylight
| Month | Crowd level | Best-time score | Avg high / low | Daylight |
|---|---|---|---|---|
| January | Average | 57 Fair | 68°F / 48°F | 10.3 h |
| February | Average | 57 Fair | 70°F / 50°F | 11.0 h |
| March | Busy | 43 Poor | 74°F / 55°F | 11.8 h |
| April | Busy | 62 Good | 80°F / 61°F | 12.7 h |
| May | Average | 64 Good | 85°F / 67°F | 13.5 h |
| June | Average | 56 Fair | 89°F / 72°F | 13.9 h |
| July | Busy | 48 Fair | 91°F / 74°F | 13.7 h |
| August | Quiet | 61 Good | 90°F / 74°F | 13.1 h |
| September | Quiet | 69 Good | 87°F / 73°F | 12.2 h |
| October★ best | Quiet | 77 Excellent | 82°F / 67°F | 11.3 h |
| November | Average | 68 Good | 75°F / 58°F | 10.5 h |
| December | Busy | 49 Fair | 69°F / 51°F | 10.1 h |
Climate normals (1991–2020) from the nearest NOAA station (USC00087826, ~1.5 mi away).
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About visiting Castillo de San Marcos
Castillo de San Marcos National Monument is a National Monument in FL and a moderately visited park, drawing about 598,000 recreation visits in 2025. Visitation has eased over the past decade, down about 13.4%. Crowds concentrate sharply by season: March is the busiest month at about 1.5× the park's average month, while September is the calmest at roughly 0.6× — a 3-to-1 swing between high and low season. Roughly 24% 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. Weather swings from an average high-season warmth near 82°F in July down to about 58°F in January, with the wettest stretch in August. About 8 months a year see comfortable average temperatures in the 50–80°F range, which is part of why crowd timing and weather timing don't always line up. The sweet spot is October: pleasant weather with noticeably thinner crowds (shoulder season). Visit then and you trade a little peak-season certainty for noticeably shorter lines and easier parking than the March rush. Daylight ranges from about 10.1 hours in midwinter to 13.9 hours near the summer solstice, which shapes how much ground you can cover in a day. A standard private-vehicle entrance pass runs about $15, 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, paired with 1991–2020 NOAA climate normals, and are updated as new monthly data is released.
Park overview
Built by the Spanish in St. Augustine to defend Florida and the Atlantic trade route, Castillo de San Marcos National Monument preserves the oldest masonry fortification in the continental United States and interprets more than 450 years of cultural intersections.
Weather & conditions
St. Augustine has a semi-tropical climate with over 300 days of sunshine each year. Summers (May-September) are hot, bright, and humid with afternoon thunderstorms common. Temperatures range from the lower 70s to the mid 90s F. Spring (March-mid-May) and Autumn (October-late November) can be pleasant with temperatures ranging from the upper 50s into the 80s F. The Winter months (December-March) are usually dry. Temperatures can be cool ranging from the upper 30s through the 60sF.
Park overview text courtesy of the National Park Service — official park site.
Where to stay near Castillo de San Marcos
Hotels, cabins, lodges and vacation rentals near Castillo de San Marcos National Monument — live availability and prices to plan your trip. October is our pick for the best balance of light crowds and good weather.
Top-rated places to stay near Castillo de San Marcos
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Getting there — nearest airports
Updated July 2026The closest airport to Castillo de San Marcos National Monument is Jacksonville International Airport (JAX), about 51 mi (1 hr 9 min drive) away.
| Airport | Distance | Drive time | Airlines |
|---|---|---|---|
| Jacksonville International Airport (JAX)Best for flights | 51 mi | 1 hr 9 min | American Airlines, Delta, Fly Lili, Silk Avia, Southwest Airlines, United Airlines |
| Gainesville Regional Airport (GNV) | 71 mi | 1 hr 47 min | American Airlines, Delta, Island Air, Silk Avia, United Airlines |
| Orlando Sanford International Airport (SFB) | 92 mi | 1 hr 58 min | Allegiant Air, Icelandair, TUIfly Netherlands |
| Orlando International Airport (MCO) | 116 mi | 2 hr 26 min | Aer Lingus, Aeromexico, Air Canada, Air Transat, Alaska Airlines, American Airlines |
| Savannah/Hilton Head Airport (SAV) | 172 mi | 3 hr 19 min | American Airlines, Delta, Silk Avia, United Airlines |
Which airport should you choose?
- Shortest drive: Jacksonville International Airport (JAX) — about 1 hr 9 min from the park.
Entrance fees
A standard private-vehicle entrance pass is about $15, typically valid for several days.
Frequently Asked Questions
October offers pleasant weather with noticeably thinner crowds (shoulder season) at Castillo de San Marcos National Monument. The park is busiest in March (about 1.5× the average month) and quietest in September.
March is the busiest month at Castillo de San Marcos National Monument, running roughly 1.5 times the park's average monthly visitation.
September is the quietest month at Castillo de San Marcos National Monument, at about 0.6× the average month — a good choice if you want to avoid crowds.
Castillo de San Marcos National Monument recorded about 598,070 recreation visits in 2025. Visitation has been falling over the past decade (-13.4%).
Based on 1991–2020 climate normals, the warmest month at Castillo de San Marcos National Monument averages about 82°F (July). See the month-by-month table above for the full picture.
Jacksonville International Airport (JAX) is the closest airport to Castillo de San Marcos National Monument, about 51 mi (1 hr 9 min drive) away.
There is no airport inside Castillo de San Marcos National Monument. Fly into Jacksonville International Airport (JAX) and drive the rest of the way — about 1 hr 9 min.
Nearby parks to visit
Keep exploring
Water quality of lakes near Castillo de San Marcos
If you are planning to swim, paddle or fish on this trip, these graded lakes are within a 40-mile drive. Grades are A–F from EPA and state-agency sampling.
- Duval-Willow Lake water qualityGrade B · 23 mi · FL
- Duval-Hidden Lake water qualityGrade B · 30 mi · FL
- Putnam-Broward Lake water qualityGrade B · 32 mi · FL
- Browsout Lake water qualityGrade B · 32 mi · FL
- Brownor Lake water qualityGrade B · 32 mi · FL
Beach water quality near Castillo de San Marcos
Beaches within a 40-mile drive, graded on multi-year bacteria sampling from EPA BEACON — worth checking before you plan a swim day.
- Anastasia State Park water qualityGrade A · 3 mi · FL
- Crescent Beach water qualityGrade A · 11 mi · FL
- Marineland Beach water qualityGrade A · 19 mi · FL
- Varn Park water qualityGrade A · 27 mi · FL
- North Flagler Pier water qualityGrade A · 31 mi · FL
Sources: National Park Service Visitor Use Statistics (1979–2025), NOAA NCEI U.S. Climate Normals 1991–2020. Crowd index = a month's visits ÷ the park's average month.