How to Check for Red Tide Before You Drive Out to the Islands

Red tide is a bloom of Karenia brevis, a naturally occurring marine organism, and it turns up along Florida's Gulf coast with no fixed schedule. It is most commonly a late-summer and autumn problem here, but it has appeared in every season and it is genuinely unpredictable.

The important practical point is that it is patchy. One beach can be affected while another five miles along the same island is clear, and conditions change day to day with wind and current. A report from last week tells you very little about this morning.

What it does

At very low concentrations it can cause respiratory irritation — a dry cough, a scratchy throat, watering eyes — which is worse for people with asthma or other respiratory conditions and is usually relieved by leaving the beach.

At higher concentrations you get fish kills along the tide line, shellfish harvesting closures and, at the top end, visible discolouration of the water.

It is not a reason to cancel a trip to Southwest Florida. It is a reason to check which beach to go to on the day.

Where to check

The Florida Fish and Wildlife Conservation Commission publishes a daily sample map, updated in the late afternoon, and a weekly status report released on Fridays. Both give sampling by county, so you can see what is happening in Lee County specifically rather than statewide.

There is also a state hotline on 866-300-9399 for current conditions.

Lee County and the state health department post beach-level advisories when conditions warrant.

Where things stood in mid-September 2026

The most recent state status report at the time of writing, dated 18 September 2026, recorded K. brevis at background concentrations in a single sample from Sarasota County and no detections elsewhere along the Southwest Florida coast. No red tide-related respiratory irritation was reported over the preceding week.

That is a snapshot, not a forecast. Blooms develop offshore and move inshore on the wind, and the situation can change within days.

Check the day you are travelling, not the day you are reading this.