Castillo de San Marcos National Monument in March
March at Castillo de San Marcos National Monument averages a daytime high near 74°F and an overnight low around 55°F, with about 3.4" of precipitation. Visitation runs about 1.5× the park's average month, which makes March a busy month here.
- Average low
- 55°F
- Average high
- 74°F
Range across the year: 48°F to 91°F
- Precipitation
- 3.4 in
- Daylight
- 11.8 hours
Roughly 13% of the park's yearly visitors come in March: about 80,000 recreation visits in a typical year, 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"). Our recommended month is October: pleasant weather with noticeably thinner crowds (shoulder season).
The daily average of about 65°F is a comfortable range for hiking and being outdoors all day. These figures are 1991–2020 NOAA climate normals from the nearest station, about 1.5 miles from the park.
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.
How March compares with the months around it
| Month | Avg high / low | Crowds | Best-time score |
|---|---|---|---|
| February | 70°F / 50°F | 1.1× Average | 57 Fair |
| March | 74°F / 55°F | 1.5× Busy | 43 Poor |
| April | 80°F / 61°F | 1.2× Busy | 62 Good |
All twelve months at Castillo de San Marcos, with the best time to visit.
Frequently Asked Questions
March averages a daytime high near 74°F and an overnight low around 55°F at Castillo de San Marcos National Monument, with about 3.4 inches of precipitation. These are 1991–2020 NOAA climate normals from the nearest station, about 1.5 miles from the park, so conditions inside the park can differ, especially at other elevations.
March is busy at Castillo de San Marcos National Monument (about 1.5× the average month). Our best-time score rates it "Poor" at 43/100. Our recommended month is October.
The busiest month is March and the quietest is September. March sits at about 1.5× the park's average, or 13% of annual visitation.
A typical March sees about 80,000 recreation visits at Castillo de San Marcos National Monument, based on National Park Service monthly counts from 1979–2025.
Where to stay near Castillo de San Marcos in March
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Top-rated places to stay near Castillo de San Marcos
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Source: National Park Service Visitor Use Statistics (1979–2025), NOAA NCEI Climate Normals 1991–2020. Updated 2026-10-11.