St. Augustine in December: Weather, Sea Temperature, Crowds and the Two Spanish Forts

ST. AUGUSTINE · DECEMBER · THE MONTH GUIDE

In December St. Augustine averages a 67.5°F afternoon, a 45.8°F night and an Atlantic sitting at 66.0°F. It is the first full calendar month clear of the Atlantic hurricane season, and Florida’s dry half of the year is already running. The trade is easy to price: you give up the swim, and you get coquina walls, a lighthouse tower and a free ferry at temperatures that let you walk from breakfast to dark.

The National Park Service dates the founding of the town to 1565. The familiar claim about the oldest continuously occupied city in the country sits on none of the NPS pages we read, so we serve the date and leave the superlative alone. For the practical frame of the trip: JAX is the nearest big airport, with 3,749,791 passengers boarded in 2024 against 27,859,783 at Orlando, and the town runs on Eastern time. Two or three nights cover December here, and our flights guide handles the routing.

On this page

• St. Augustine weather in DecemberHighs of 67.5°F and 4.4 wet days
• Can you swim in December?A sea at 66.0°F
• Crowds and the lodging taxThe holiday peak and 11% on the room
• Things to do in DecemberCastillo, Fort Matanzas, the lighthouse
• A two-day planTwo days built around a 5:29 p.m. sunset
• December, November or January?How the three months compare
• Is December a good month to visit?Our verdict, and who should shift dates

The numbers below all carry a December date. Where to sleep, how to drive the coast and what a Florida week costs belong to the lodging guide, getting around Florida and trip cost. The neighboring months have their own pages, drawn from the same station: November and January.

St. Augustine weather in December: average highs, lows and rain days

Every figure here comes from the NOAA NCEI monthly normals for 1991-2020, station USW00013889: the thermometer at Jacksonville International Airport, roughly an hour up the coast. That is a real instrument rather than a reanalysis grid cell, and we would rather name the station than pretend the gauge stands in the old town. Read 67.5°F and 45.8°F as regional normals for the month, and expect any single week to wander off them in both directions.

2.78 inches fall across the month, but the count that shapes a trip is 4.4 days at 0.10 inch or more: measurable rain about one day in seven. Heavier weather is rarer, at 0.8 days of an inch or more, so roughly four Decembers in five get one genuine soaking and the others settle for gray hours. Plan outdoors first and hold one indoor afternoon in reserve, and the arithmetic is on your side.

The gap between afternoon and dawn is 21.7°F, and 3.6 nights in an average December drop to 32°F or below. Packing follows from that: a fleece you shed by 11 a.m., a real jacket for after dark, long pants for the breeze on an open gun deck. Shorts work at 2 p.m. and stop working at 6. Leave the parka home, and bring shoes that cope with cobbles and fort ramps.

December 15 runs 10 hours 17 minutes, from a 7:12 a.m. sunrise to a 5:29 p.m. sunset, Eastern time. The practical consequence: the outdoor half of the day is over before dinner, and the Castillo’s last admission at 5:00 p.m. lines up almost exactly with the light. Anything you want to see in daylight goes before 4 p.m., and the evening turns into a town-and-table affair.

Can you swim in St. Augustine in December? Sea temperature and what it feels like

Sea surface off St. Augustine averages 66.0°F in December in the Open-Meteo Marine record, taken as the mean of daily maxima over 2015-2024. The wording matters: it averages the warmest point of each day, so it reads a shade above a true 24-hour mean, and a 7:30 a.m. dip starts below the headline. Tables built on full-day averages will print a cooler December for exactly the same water.

At 66.0°F most American swimmers call the water bracing and get out fast. Surfers wear a suit, children go in regardless, and air at 67.5°F gives you very little back once you are out of it. Two rules govern the sand itself: Florida’s beach warning flags carry no obligation, since no law compels a beach to fly any of them, and under Florida Statutes s. 163.035 the wet sand below the mean high-water line is public while dry sand above it can be private.

We could not verify a December wind or wave series for this stretch of coast, so we give no figures for either. What we can date is the season: the Atlantic hurricane season runs June 1 to November 30 and peaks on September 10, so a December booking carries no tropical risk inside the official window. Ask a lifeguard or read the flag pole before going in, and treat an empty winter beach as unguarded until you see otherwise.

How busy is St. Augustine in December? Crowds, the lodging tax and the holiday peak

December splits in two. The first three weeks belong to the quiet end of the fall, and the last ten days fall inside the holiday stretch that our Florida timing guide names as one of the state’s two annual crowd peaks, alongside spring break. We found no occupancy or room-rate series for St. Johns County, so we crown no month cheapest and none dearest.

That split decides how you book. Nights between the 1st and the 20th behave like ordinary off-season nights. Nights from Christmas Eve through New Year’s Day compete with the whole state at once, and our own habit is to lock those rooms and seats in early fall, two to three months out. JAX boarded 3,749,791 passengers in 2024 against Orlando’s 27,859,783: fewer flights means fewer seats to shuffle once they go.

On the bill, St. Johns County levies a 5.0% transient rental tax, filed and paid alongside the 6% state sales tax, per Florida Department of Revenue form DR-15TDT. Eleven percent therefore lands on the room rate before any property adds a fee of its own. We verified no hotel name and no nightly rate here, so we give no room figure; our trip-cost guide carries the statewide tiers.

The one upgrade that changes December rather than decorating it is walking distance. Usable light ends at 5:29 p.m., and a bed inside the old town turns that into a short walk from fort to dinner instead of a drive at dusk and a hunt for a space in the dark. Beyond that, the month asks for money in small amounts: a $15 fort ticket, a tank of gas for the run south, dinner indoors.

Things to do in St. Augustine in December: the Castillo, Fort Matanzas and the lighthouse

The advantage of these dates at all three sites is climbing weather. A 67.5°F afternoon is the difference between a tower stairwell you enjoy and one you endure, and the same holds for an open gun deck with no shade anywhere on it. The month also sits clear of the June 1 to November 30 hurricane season, so no tropical week reroutes the trip. Short days are the offset: 9 a.m. openings suit the light, and late starts waste it.

Castillo de San Marcos charges $15.00 for anyone 16 and over, and the ticket stays valid for 7 consecutive days; children 15 and under enter free with an adult. First admission is 9:00 a.m., last admission 5:00 p.m., and everyone exits at 5:15 p.m. The Park Service calls it the oldest masonry fortification in the continental United States, and notes the Spanish built with coquina because it was the only local stone. Fort Matanzas preserves a coquina watchtower completed in 1742, guarding the southern approach to the settlement.

The lighthouse keeps its winter schedule from October 1 to February 28, 9:00 a.m. to 6:00 p.m., with the last ticket sold at 5:30 p.m. In December that final ticket goes out one minute after the 5:29 p.m. sunset, so the top of the 1874 tower becomes a night view rather than an afternoon one. Children under 44 inches cannot go up, and anyone taller climbs under their own power. We could not read a general admission price, so we quote none.

Free and verified: all areas of Fort Matanzas, ferry included. The catch is the boarding pass, collected at the Fort Matanzas Visitor Center and not at the city visitor center downtown, with one pass required per person of any age. The ferry service year runs October 1 to September 30, though its daily departure times were not readable at the source, so call before driving south. These two forts are two of Florida’s eleven Park Service units, and neither is a National Park: in Florida that title belongs to Everglades, Biscayne and Dry Tortugas.

St. Augustine in December: a two-day itinerary

Day one runs between the 7:12 a.m. sunrise and the 5:29 p.m. sunset. Coffee in the dark, then the Castillo at its 9:00 a.m. first admission while the gun deck is still cold, and give the walls two hours. Lunch indoors at midday, old streets while the sun is highest and the 67.5°F is real, then a lighthouse ticket bought by 5:00 p.m. so the tower comes with the last of the light. Dinner indoors, jacket on.

Day two goes south to Fort Matanzas: the visitor center first for the free passes, one per person, then the ferry across to the 1742 watchtower, the whole outing costing nothing. Be back in town by mid-afternoon, since the light quits at 5:29. If one of the month’s 4.4 wet days lands on you, the Castillo ticket’s seven consecutive days makes a second visit free, and the only date that defeats the plan outright is December 25, when the fort closes.

St. Augustine in December vs November and January

Side by side, November holds 73.2°F by day and 51.3°F at night, with 2.00 inches of rain over 3.9 wet days and a 72.7°F sea. December settles at 67.5 and 45.8, 2.78 inches, 4.4 wet days and 66.0°F water. January keeps going down: 65.5 and 42.9, 3.28 inches, 5.2 wet days, 62.6°F. One station, one set of 1991-2020 normals and one marine record cover all three columns.

Shift four weeks back and you gain 5.7°F of afternoon and 6.7°F of sea, enough to make swimming plausible again, while keeping one foot inside a hurricane season that runs to November 30. Shift four weeks forward and you lose 2.0°F of afternoon and 3.4°F of water, and you take on half an inch more rain across nearly a full extra wet day. Our November page and January page carry both in full.

Is December a good time to visit St. Augustine?

Yes, if your trip is walls, streets and a tower. The month delivers 67.5°F afternoons, measurable rain about one day in seven, no tropical risk, and a fort where every child 15 and under walks in free. No, if your trip is swimming or sunbathing: 66.0°F water and 3.6 nights at or below freezing make for a coastal town in winter, not a beach vacation.

When the water is the point, book November instead: 73.2°F days, a 72.7°F sea, 2.00 inches of rain over half a wet day fewer, at the cost of the season’s last thirty days of storm watching. January is the one of the three to skip, colder by 2.0°F in the afternoon, wetter by half an inch and 3.4°F down in the ocean.

Only in December do you get a 5:29 p.m. sunset with the air still at 67.5°F: the lighthouse tower can be climbed into the dark without a coat, and without a storm check on the morning of the flight.

The last word

Decide on the water first and the rest falls into place: swimming means November, walking means December, and the Castillo’s seven-day ticket means no fort visit ever has to be squeezed into one weather window. Carry one thing south on the second day. The river you cross to Fort Matanzas is named for an event, matanzas being the Spanish word for slaughters, after the massacre of French Huguenots there, and the Park Service is direct about the stake: whoever held Florida held the rich shipping lanes coming out of the Spanish Caribbean.

Sources & data for this guide

• December normals, highs, lows and precipitation · NOAA NCEI monthly normals 1991-2020, station USW00013889 (Jacksonville International Airport) · checked Sep 23, 2026
• Wet-day and freeze counts (4.4 days at 0.10 in, 0.8 day at 1 in, 3.6 nights at 32°F) · NOAA NCEI 1991-2020 · checked Sep 23, 2026
• Sea surface 66.0°F, mean of daily maxima 2015-2024 · Open-Meteo Marine API · checked Sep 23, 2026
• Daylight of 10h 17m, sunrise 7:12 a.m. and sunset 5:29 p.m. on Dec 15, converted to Eastern time · sunrise-sunset.org · checked Sep 23, 2026
• Hurricane season dates and the Sep 10 peak · NOAA National Hurricane Center · checked Sep 23, 2026
• Castillo de San Marcos fees, hours and coquina construction · National Park Service, Fees, Hours and Stories pages · checked Sep 7-8, 2026
• Fort Matanzas free entry, boarding passes, the 1742 watchtower and the river name · National Park Service · checked Sep 23, 2026 · daily ferry departure times were not readable at the source
• Lighthouse winter hours and the 44-inch tower rule · St. Augustine Lighthouse & Maritime Museum · checked Sep 23, 2026 · general admission price not read
• Lodging tax, 5.0% county transient rental tax with 6% state sales tax · Florida Department of Revenue form DR-15TDT · checked Sep 23, 2026
• JAX and MCO 2024 passenger boardings · Federal Aviation Administration, CY2024 · checked Sep 23, 2026
• Beach warning flags and beach access under Florida Statutes s. 163.035 · Florida Statutes and Volusia County Beach Safety · checked Sep 23, 2026
• Founding year 1565 · NPS Fort Matanzas, History & Culture · checked Sep 23, 2026 · the oldest-city superlative is on none of the NPS pages we read
• We verified no hotel, no restaurant and no December event date for the town, and found no occupancy series, so we name none.

To plan your stay

• Things to Do in St. Augustine: Castillo Tickets, Fort Matanzas Ferry and Lighthouse Hours
• Where to Stay in St. Augustine: Historic District, the Beach and the 5% Lodging Tax
• Airport to St. Augustine: JAX, MCO, Rental Cars and Eastern Time
• St. Augustine Know Before You Go: Castillo Fees, the Fort Matanzas Ferry Pass and Beach Rules

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