Castillo de San Marcos National Monument in December
December at Castillo de San Marcos National Monument averages a daytime high near 69°F and an overnight low around 51°F, with about 3" of precipitation. Visitation runs about 1.2× the park's average month, which makes December a busy month here.
- Average low
- 51°F
- Average high
- 69°F
Range across the year: 48°F to 91°F
- Precipitation
- 3.0 in
- Daylight
- 10.1 hours
Roughly 10% of the park's yearly visitors come in December: about 64,000 recreation visits in a typical year, based on National Park Service monthly counts from 1979 to 2025.
That makes December the 2nd-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 December rates 49/100 ("Fair"). Our recommended month is October: pleasant weather with noticeably thinner crowds (shoulder season).
The daily average of about 60°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 December instead steps outside that summer crush — the single biggest lever on how crowded the park feels.
You'll have about 10.1 hours of daylight in December to explore — near the year-round minimum.
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 December may feel a touch quieter than it once did.
How December compares with the months around it
| Month | Avg high / low | Crowds | Best-time score |
|---|---|---|---|
| November | 75°F / 58°F | 1.0× Average | 68 Good |
| December | 69°F / 51°F | 1.2× Busy | 49 Fair |
| January | 68°F / 48°F | 1.0× Average | 57 Fair |
All twelve months at Castillo de San Marcos, with the best time to visit.
Frequently Asked Questions
December averages a daytime high near 69°F and an overnight low around 51°F at Castillo de San Marcos National Monument, with about 3 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.
December is busy at Castillo de San Marcos National Monument (about 1.2× the average month). Our best-time score rates it "Fair" at 49/100. Our recommended month is October.
The busiest month is March and the quietest is September. December sits at about 1.2× the park's average, or 10% of annual visitation.
A typical December sees about 64,000 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 December
Booking a December trip to Castillo de San Marcos National Monument? Compare hotels, cabins and vacation rentals near the park with live December availability and prices.
Top-rated places to stay near Castillo de San Marcos
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See the full ranking of the best national parks to visit in December.
Source: National Park Service Visitor Use Statistics (1979–2025), NOAA NCEI Climate Normals 1991–2020. Updated 2026-10-11.