St. Augustine in May: Weather, Sea Temperature, Crowds and Prices

ST. AUGUSTINE · MAY · 29.9° N

An average May afternoon in St. Augustine reaches 85.9°F, the dawn sits at 63.9°F, and the ocean off the beaches runs 77.6°F, all of it ahead of the Atlantic hurricane season that opens June 1. NOAA’s 1991-2020 normals put 3.42 inches of rain across the month, spread over 4.6 days wet enough to measure. For a town whose two federal monuments both stand outdoors, that combination does real work: you can walk coquina walls at nine in the morning without wilting, and still be on sand at seven in the evening.

What you give up in May is bath-warm water. June’s sea reaches 82.2°F and charges 7.60 inches of rain across 9.7 wet days for it, more than double this month’s count. Go the other way and April keeps mornings at 56.4°F with the ocean at 71.8°F. That is swimmable for the stubborn and nobody else. Four weeks in either direction changes the trip more than most travelers expect, so the date is worth as much thought as the hotel.

On this page

• Average highs, lows and rain days in May85.9°F days, 4.6 wet days
• Can you swim in May?The sea at 77.6°F, and what that feels like
• Crowds, lodging tax and booking11% on the nightly line, and what we could not price
• Things to do: the Castillo, Fort Matanzas, the lighthouse$15 forts, free ferries and a 6:00 p.m. last ticket
• A two-day plan for MayTwo days built on a 9 a.m. opening
• May against April and JuneHow the three months compare, degree by degree
• Is May a good month to go?Who should book it, who should shift
• The month before, in the same detailSt. Augustine in April

Anything that is true in St. Augustine all year sits elsewhere in the cocoon: the statewide season logic in when to visit Florida, the driving and parking layer in getting around, the budget tiers in what a Florida trip costs. Everything below is dated to May.

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

Every figure here comes from NOAA NCEI’s 1991-2020 monthly normals for station USW00013889, a real thermometer at Jacksonville International Airport, inland and north of the old town rather than on the beachfront. An inland station does not read the same as a seafront one, so treat 85.9°F by day and 63.9°F at night as the shape of the month rather than the number on a beach umbrella. Rainfall on the same series comes to 3.42 inches, which is a normal and not a forecast.

Those inches arrive in few enough visits to plan around. An average May records 4.6 days with at least a tenth of an inch, roughly one day in seven, and a single day with an inch or more. Translated into a week on the ground: six mornings out of seven start dry, and the month’s genuine soaking tends to be one event rather than a gray stretch. A folding umbrella covers it. Rain gear built for a Pacific Northwest winter does not earn its space in the bag.

Between the high and the low sits a 22-degree spread, and you will meet both ends inside one day. A 6:30 a.m. walk at 63.9°F wants a light layer; the same street at four in the afternoon wants none of it. Pack thin long sleeves you can carry rolled up by ten, a hat, and shoes you can rinse, because the walk from sand back to pavement is short here and the salt goes with you.

On May 15 the sun rises at 6:30 a.m. and sets at 8:13 p.m. Eastern, 13 hours 43 minutes of daylight by sunrise-sunset.org, converted to America/New_York. St. Augustine sits east of the Apalachicola River, so Eastern is the clock all year. The dividend lands after dinner: the Castillo clears its last visitors at 5:15 p.m., and nearly three hours of usable light remain after that.

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

Sea surface off St. Augustine averages 77.6°F in May in the Open-Meteo Marine record for 2015-2024. Read that number with its caveat attached: it is the mean of daily maxima, not a round-the-clock average, so it sits a shade warmer than tables built on 24-hour readings. Water at seven in the morning will be under it, water at four in the afternoon at or above it. Other sources you meet online may quote a degree or two lower for exactly this reason.

In practice, 77.6°F is swimming without a wetsuit and without a countdown. It runs 5.8 degrees above April’s 71.8°F and 4.6 below June’s 82.2°F, so the first ten seconds still register as cold before they stop mattering. A long session will cool you down, and that is the point in a month whose afternoons average 85.9°F: the exit onto hot sand is the comfortable part. Children stay in longer than the adults watching them.

We found no verified wind or swell series for this stretch of coast in May, so we quote none. What is fixed is the flag code: double red means the water is closed, red high hazard, yellow medium, green low hazard with caution, and purple, flown alongside another flag, means dangerous marine life. No Florida law compels a beach to fly any of them, so read the stand rather than an empty pole. One more rule to carry: wet sand below the mean high-water line is public, dry sand above it can be private (Florida Statutes s. 163.035).

How busy is St. Augustine in May? Crowds, prices and the demand peak

May falls one month past the end of Florida’s statewide dry season, November through April, and one month short of the hurricane season that opens June 1 and peaks around September 10. We found no occupancy series and no monthly room-rate series for St. Johns County, so we crown no month cheap and no month expensive. What the calendar does say plainly: the storm risk that reprices September travel is not a factor in May, and neither is a school-holiday week.

Most trips fly into Jacksonville, JAX, a medium hub that boarded 3,749,791 passengers in 2024 against Orlando MCO’s 27,859,783. A medium hub carries fewer daily options than the state’s busiest airport, so fixed May dates are worth pricing well before the weekend you want; our flights guide handles the routing question. Once you land, nothing outdoors here needs a reservation. The Castillo sells tickets at the door from 9:00 a.m., seven days a week.

Whatever the room costs, the tax is knowable. St. Johns County levies a 5.0% transient rental tax, filed and paid with the 6% state sales tax, so 11% lands on the nightly line (Florida Department of Revenue, form DR-15TDT). Short-term rentals owe it too. We could not verify any hotel rate, any rental rate or any restaurant price for May, so we put no dollar figure on a night here and no average on a dinner.

The one ticket worth buying on arrival day is the Castillo’s: $15 for adults 16 and over, valid seven consecutive days, with under-16s admitted free when an adult is with them. At that price the fort stops being a single visit and becomes a 9 a.m. habit through the stay, which is the coolest hour May offers. The lighthouse we cannot price: no general-admission rate could be read at the source, and we will not invent one.

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

Two usable windows a day is what this month gives that June does not. A 63.9°F dawn makes the early one bearable, and an 8:13 p.m. sunset makes the late one long. June keeps the light but spends 9.7 days of it under measurable rain, against 4.6 in May, and opens the hurricane season on the first of the month. April has the cooler air and the cold water. May is the overlap where outdoor plans and swimming plans stop competing.

Castillo de San Marcos is, in the Park Service’s own wording, the oldest masonry fortification in the continental United States, built of coquina because it was the only local stone. First admission 9:00 a.m., last admission 5:00 p.m., everyone out at 5:15, open daily except Thanksgiving and Christmas, $15 for ages 16 and up. The St. Augustine Lighthouse runs 9:00 a.m. to 6:30 p.m. from March 1 to September 30 with the last ticket sold at 6:00 p.m. The 1874 tower is included with general admission, and children under 44 inches cannot go up.

Coquina does not care what month it is. The air does. At 85.9°F, the two comfortable slots at the Castillo are the 9:00 a.m. opening and the last hour before the 5:15 p.m. clear-out, and the same walls sit under 89.9°F averages by June. At the lighthouse, a 6:00 p.m. last ticket falls a little over two hours before sunset in May, so the climb happens in the cooling half of the day rather than against it.

Fort Matanzas National Monument costs nothing at all, ferry to the fort included. The catch is the paperwork: boarding passes are free but collected at the Fort Matanzas Visitor Center, not at the city visitor center downtown, and every family member needs a pass whatever their age. The Fort Ferry Service runs an October 1 to September 30 year. Confirm the ferry’s daily departure times on the day. The coquina watchtower it serves was completed in 1742 to guard the southern approach.

St. Augustine in May: a two-day itinerary

Day one runs on the fort’s clock. Be at the Castillo for the 9:00 a.m. first admission, when the air is closer to the 63.9°F overnight low than to the 85.9°F peak, and keep the ticket: it re-admits for seven consecutive days. Give the middle of the day to lunch and anything with a roof. At 4:30 p.m., buy the lighthouse climb before the 6:00 p.m. cutoff. That still leaves the beach, or dinner outdoors, with light until 8:13 p.m.

Day two goes south to Fort Matanzas: collect the free boarding passes at its own visitor center first, then ride out to the 1742 watchtower, then swim in the afternoon when the 77.6°F water is at its daily warmest. If the sky turns, remember the arithmetic: only one day in an average May delivers an inch or more of rain, and it usually comes and goes. Check the beach flags rather than the clouds, move the swim, and put the fort walk in its place.

St. Augustine in May vs April and June

Line the three up and the jump is not in the air, it is in the water and the rain. April to May adds 6.1 degrees to the afternoon and 5.8 to the sea, for 0.49 of an inch more rain and two-tenths of a wet day. May to June adds only 4.0 degrees by day but 4.18 inches of rain and 5.1 more measurable days, taking the count from 4.6 to 9.7. The sea gains 4.6 degrees in that same step, to 82.2°F.

Shift four weeks earlier and you trade swimming for comfort: 71.8°F water, 56.4°F mornings, and the driest of the three months at 2.93 inches. Shift four weeks later and you buy the warmest sea of the three, then pay with an afternoon storm pattern and the opening of hurricane season on June 1. Booking flexible rates matters from June onward for that reason, as our statewide calendar spells out. In May it is a weather question, not a risk question.

Is May a good time to visit St. Augustine?

For anyone who wants to swim and walk on the same trip, yes, and it is the first month of the year where both work: 77.6°F water, 4.6 wet days, no hurricane season. For anyone who overheats, the answer softens. Normal afternoons at 85.9°F with Florida humidity make a midday of outdoor sightseeing a poor idea, and the two forts are exposed. Families with a child under 44 inches should also know that one of them cannot climb the lighthouse tower.

If the heat is the deciding factor, take April instead. Afternoons average 79.8°F, mornings 56.4°F, rain runs 2.93 inches over 4.4 days, and every fort hour of the day is usable rather than two of them. The cost is the ocean at 71.8°F, so build that trip around walls, towers and the river rather than the surf, and read the April page before you lock dates.

No other month pairs a swimmable sea with under five measurable rain days and a calendar clear of hurricane season.

The last word

Book the May dates, then buy the $15 Castillo ticket on the day you arrive and use all seven of its days at nine in the morning. Two of Florida’s eleven National Park Service units sit in this one town, and neither is a National Park: that title belongs to Biscayne, Dry Tortugas and the Everglades. The Park Service dates the founding of St. Augustine to 1565, though the “oldest continuously occupied city” line repeated everywhere appears on none of the NPS pages we read. And the river you cross for the free ferry carries the record of an event: matanzas is Spanish for slaughters.

Sources & data for this guide

• May normals: 85.9°F high, 63.9°F low, 3.42 in, 4.6 days at 0.10 in or more, 1.0 day at 1.00 in or more · NOAA NCEI monthly normals 1991-2020, station USW00013889, Jacksonville International Airport · checked Sep 23, 2026
• April and June normals used in the comparison · same NOAA NCEI 1991-2020 series, same station · checked Sep 23, 2026
• Sea surface 77.6°F, mean of daily maxima 2015-2024 · Open-Meteo Marine API · checked Sep 23, 2026
• Daylight 13 h 43 m and sun times on May 15, converted to America/New_York · sunrise-sunset.org · checked Sep 23, 2026
• Hurricane season June 1 to November 30, peak September 10 · 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 and 8, 2026
• Fort Matanzas free entry, boarding passes, 1742 watchtower, 1565 founding, river name · National Park Service, Fort Matanzas · checked Sep 23, 2026
• Lodging tax 5.0% county plus 6% state · Florida Department of Revenue, form DR-15TDT · checked Sep 23, 2026
• Lighthouse hours, last ticket and 44-inch tower rule · St. Augustine Lighthouse & Maritime Museum · checked Sep 23, 2026
• JAX 3,749,791 and MCO 27,859,783 enplanements · Federal Aviation Administration, CY2024 · checked Sep 23, 2026
• Beach warning flags and dry-sand access · Florida Statutes s. 380.276 and s. 163.035, Volusia County Beach Safety · checked Sep 23, 2026
• We could not verify the lighthouse general-admission price, the Fort Matanzas ferry departure times, or any hotel rate, rental rate or occupancy figure for May · we give no numbers for those, and no May event dates are claimed.

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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