In order of how often they actually catch people out. Sharks are not on the list.
1. Rip currents
The tidal range here is 6 to 7.4 ft — large for Florida — and that volume of water moves through the gaps in the sandbar system twice a day. A falling tide with surf running is the classic setup.
If you are caught: swim parallel to the beach, not against the pull, until you are out of it, then come in at an angle. Rip currents has the detail, and safety and flags covers the warning system.
Only Main Beach Park has any lifeguard cover we have confirmed, and it is seasonal. The other twelve-plus miles are unguarded at all times — see are there lifeguards. Choose your access accordingly if anyone in the group is a weak swimmer.
2. The tide itself
This is the one visitors do not see coming.
At low water the sea retreats a long way over a very flat beach and leaves wadeable shallows over the exposed sandbars. They are warm, calm and shallow, and they are the best free thing on this island for a small child.
On the flood, the water comes in behind you. Not at you — behind you, filling the channel between the sandbar and the shore while you are looking out to sea. Do not let the water get between you and the beach, and check the tide table before you walk out onto one.
3. Heat and humidity
July averages 90.7°F with matching humidity, and June to September all sit in the high 80s. There is no natural shade on this beach and none on the Fort Clinch ramparts, where the brickwork holds heat.
The practical rule is the one locals use: do the outdoor thing in the morning, be somewhere shaded from mid-afternoon, come out again in the evening. Carry more water than you think, especially on the marsh trails, which are flat, exposed and longer than they look.
4. Thunderstorms
Near-daily from June to September, arriving fast. September is the wettest month at 7.19 inches across about nine rain days.
When you can hear thunder the beach is over for the day — that is not a judgement call. A boat trip or kayak trip will usually be cancelled for you, and a captain who cancels is doing you a favour.
Hurricane season runs June to November: read hurricane season before booking a late-summer week.
Wildlife, in proportion
Alligators are resident in the Egans Creek Greenway ponds and channels and are frequently visible from the trail, which comes right to the water in places. Keep well back from the edges, keep children in hand, keep dogs on a short lead. This is a functioning wild marsh rather than a managed exhibit.
Sharks are present, as they are the length of the Florida coast, and the tidal creeks are nursery habitat. Bites are very rare — are there sharks puts it in proportion. The rip currents above are the thing to plan around.
Sea turtles nest on this beach. That changes what you do rather than what happens to you: no lights on the beach at night in season, fill in holes, take your kit away. See sea turtles.
Insects in the marsh from spring through autumn are a comfort problem rather than a danger, and repellent is equipment.
Two things this page will not tell you
Where the nearest hospital or urgent care is. We have not confirmed a single medical facility's name, address or hours, and this is the last subject on which we would guess — an out-of-date address in an emergency is worse than nothing. Use your phone's maps or ring 911. Our questions hub lists this among the answers we are holding back and why.
Anything medical. We are a visitor guide.
Everything above is drawn from the tide and climate data we hold and from pages on this site that carry their own sources. For anything safety-critical in the moment — surf, weather, storms — cite NOAA and the National Weather Service directly rather than this site, because our conditions page is a build-time snapshot. It says so itself: conditions.