What does each beach flag color mean? A guide to the warning system amid severe weather and shark attacks.

Nothing says a hotter day like the beach, but beyond the coast there are a series of dangers, from return currents and strong waves to shark attacks and swaying jellyfish. On land, however, you’ll likely find a flag warning of potential dangers, and whether it’s purple, yellow, red, or blue, it can indicate what danger might be lurking in the waters.

A day at the beach can be a lot of fun, but when swimming in the ocean be aware of its conditions and the other life forms that may be present below the surface. According to the American Lifesaving Association, beach flags and their designated meanings were created to help inform people about this. Many of these flags are also used around the world.

So what exactly are beach flags and what do they mean? Here are the flags approved by the association for use on beaches where lifeguards are trained to its standards.

green beach flag

When the sea is calm or mild, the beach may not have a flag flying, as the International Life Saving Federation decided not to officially adopt the color. But some locations will fly a green flag to indicate the water is safe.

The international body did not adopt the green flag because “there is always a potential danger present,” states the USLA on its website, “and the view that it is better to notify people when conditions are unusually challenging, rather than suggesting that they are always completely safe.”

yellow beach flag

Yellow flags indicate that there is a “medium danger” on the beach, says the association, with the ocean presenting moderate surf conditions and/or currents. When this flag is raised, weak swimmers should avoid entering the water, while others should exercise “greater care and caution.”

Beachgoers should be aware of the potential for return currents, which can form anywhere there are waves in any type of weather or condition. These currents can be deadly and are most often seen at low tide, when waves are at least 2 feet high.

red beach flag

As with many things, red indicates danger on the beach. The association states that when this bold red flag is flying, it means there are difficult conditions on the water, such as strong waves and currents. At this point, the association said, “all swimmers are discouraged from entering the water,” and those who choose to do so anyway “should exercise extreme caution.”

Red double beach flag

If you see two red flags – or two red flags stacked on top of each other – it means the water is closed to the public.

purple beach flag

On the beach, purple means pests — but don’t worry, that doesn’t necessarily include sharks. Purple flags will be displayed when marine animals that could cause minor injuries, such as jellyfish and stingrays, are in the area. The association states that the flag is “not intended to indicate the presence of sharks,” although some destinations may use purple to indicate their presence. Always check your destination’s specific alert system before going to the beach.

Red and yellow beach flag

If you see a single flag that is half red and half yellow, the area you are in is among the safest on the beach. Flags indicate that an area is protected by lifeguards and closely supervised. According to the association, a single flag can be posted to show an area where swimming is permitted and is being supervised, or it can be used in spaced pairs to more clearly designate a supervised zone.

Red and white beach flag

Flags divided into red and white mean one thing: it’s time to get out of the water. If one of these flags is flying, swimmers should immediately evacuate the waves due to an emergency such as water contamination, water rescue, or even the presence of sea creatures with the potential to cause great harm, such as sharks.

Sometimes, however, purple flags or double red flags are used when sharks are present. These guidelines established by the association are guidelines and localities may use flags as they see fit.

Black and white beach flag

Surfers will want to keep an eye out for the black and white flags. These flags, which have these quartered colors, are used when an area is designated only for surfboards and other non-powered vessels. Swimmers need to stay out of the areas to avoid injuries or other problems.

Yellow beach flag with central black ball

If surfers and paddleboarders see this flag – a yellow rectangle with a large black circle in the center – it means that surfboards and other non-powered craft cannot be used.

orange windsock

Windsocks are a widely used scientific tool, but on the beach they can save lives. If an orange windsock is up, not only can you see which direction the wind is going and how strong it is, but it also indicates that it is not safe to use inflatable objects in the water, the association says. This can be particularly important for those who use inflatable rafts or swim rings for their children.

A beach warning reminder

Although these are the flags used by the association, some areas may use flags slightly differently. Florida, for example, has a uniform state system that uses only purple, green, yellow, red, and double red flags. Before heading to the beach, it’s always best to look up the beach flag system for that specific location, or even ask the lifeguards you see on the sand and check the local weather to see if any storms or currents are expected.