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Tides, Swell & Wind: What to Know When Boating or Kayaking in Charleston

Understanding Tide, Swell and Wind When Boating or Kayaking in Charleston

If you’re not used to coastal navigation, boating or kayaking in Charleston will be a unique experience. Here’s an overview of what you need to know to stay safe and have an enjoyable day on the water.

Charleston is one of the most popular places for boating in the United States—and for good reason. From the postcard-perfect backdrop of the Ravenel Bridge in the Charleston Harbor to Charleston’s uninhabited barrier islands, there is no shortage of boating destinations in the Holy City. There are also several popular inshore boating destinations, and Charleston is, without a shadow of a doubt, a fisherman’s paradise.

Charleston is also a great place to kayak. You can explore miles of rivers and creeks—from Mount Pleasant all the way down to the ACE Basin—and you can reach several of Charleston’s uninhabited barrier islands by kayak as well. In fact, because of the tides, several of these islands are easier to visit by kayak than by boat.

But, regardless of whether you are boating or kayaking, there are some important factors to consider before you hit the water. If you are not used to navigating by the coast, boating or kayaking in Charleston will be unlike any time you’ve spent on the water previously. You need to plan ahead. You need to make an informed decision about where and when to go, and you need to be prepared to change your plans if the weather or water conditions don’t cooperate.

Boating in Charleston Harbor--need to check tide, swell, and wind
Conditions in the Charleston Harbor can vary widely. Even when the conditions are favorable in the morning, it is important to monitor the swell and weather forecast throughout the day.

3 Key Factors for Kayaking and Boating in Charleston: Tides, Swell, and Wind

We recently published a Guide to Boating in Charleston. In the guide, we cover 25 tips for having a safe and enjoyable day on the water. Here, we’re covering three key factors in a bit more depth: tides, swell, and wind.

1. Planning for (and Dealing with) the Tides

On average, the tide shifts six feet every six hours in Charleston. While this doesn’t make much of a difference if you are in the channel or cruising the Intracoastal Waterway (ICW), this shift is more than enough to leave you beached in many areas. There are sandbars in the Charleston Harbor and several of Charleston’s rivers that are above water at low tide; and, if you go to the beach on a falling tide, you could easily find yourself stranded until the tide comes back in.

Although these specific concerns are less worrisome for kayakers, if you are paddling in Charleston’s marshes, you do need to pay attention to the tides. This is especially true during spring tides, when the low tide is lower than average. If you run out of water, it will come back eventually, but you could find yourself stuck in the pluff mud without a great way to get yourself out.

So, how should you plan for the tides when boating or kayaking in Charleston? Here are some important tips to keep in mind:

  • Know Where You’re Going – It is important to have a plan (and leave your plan with someone you trust) any time you go boating or kayaking. But, this is especially true when you’ll potentially be dealing with the tides. Once you decide on a route, you can check the tides; and, if they aren’t in your favor, you can adjust your plan as necessary.
  • Check the Tide at Your Put-in Point and Your Destination – With a route in mind, you should check the tide at your put-in point and at your destination. While the high tide and low tide times should be similar, they can vary by an hour or more depending on how far inland you’re going or how far you’re heading up the coast.
  • Check the Depth Charts – Along with checking the tides, you should also check the depth chart along your entire route. Because Charleston has so many sandbars, you do not want to rely solely on your depth finder. If you don’t have a depth chart, you can download an app like Seapilot or Hip Charts (there are many other options as well). Additionally, if you’re going to the beach at Capers Island or Morris Island, the topography of the seafloor in these areas is highly variable. While you could have plenty of water in a particular spot, you could be at risk for getting beached just a few yards to either side.
  • Make Sure You Know Your Boat’s (or Kayak’s) Draft – Perhaps this could go without saying, but you need to make sure you know your boat’s (or kayak’s) draft. This is especially important if you are renting a kayak or you have recently joined one of Charleston’s boat clubs. While flats boats can cruise through a foot of water (and in some cases even less), most bowriders, deck boats, and center consoles need at least three feet of water beneath them.
  • If You’re Going to the Beach, Go During the Rising Tide – One of the safest ways to avoid getting stranded if you’re going to the beach is to go during the rising tide. If you get to the beach just after slack tide, you’ll have the whole morning or afternoon to spend at the beach without worrying about whether your boat is still floating. On the other hand, if you anchor while the tide is falling, you’ll need to make sure that you’ll still have enough water to get underway when you’re ready to go home.

Another factor to consider—especially for kayakers—is that the tidal current is strongest at the midpoint between high tide and low tide. This is when it will be most difficult to go against the tide. If it’s also windy, it could be extremely difficult to make progress paddling. While you’ll still be able to make progress on your boat, you’ll use significantly more fuel when fighting a strong tidal current. If you’re planning a long day out, this is something you will need to factor into your planning as well.

2. Understanding the Swell

When deciding where to kayak or take your boat, it is also important to consider the swell. Swell is defined as the surface waves generated by environmental factors including wind, gravity, and storms that could be hundreds or thousands of miles away. Even on an otherwise clear day with a favorable tide, a bad swell could make boating or kayaking an extremely uncomfortable—and potentially dangerous—experience.

You can look up the swell where you plan to go boating or kayaking using a variety of marine navigation apps. Windy is a popular (and free) choice, though there are also plenty of alternatives. When checking the swell, you will see two numbers, both of which are important:

  • Swell Size – This is the height of the swell (or waves), measured from peak to trough. For kayakers, a swell of a foot and a half or more can start to get uncomfortable. For boaters (with a boat that is at least 20 feet in length), a two-foot swell size can be okay as long as the swell period is reasonably long; but, if the forecast calls for a three-foot swell, most inexperienced boaters will want to stay home.
  • Swell Period – The swell period is the amount of time (measured in seconds) from one peak to the next. As a general rule, in order for conditions to be favorable for kayaking or boating, the swell period should be at least twice the swell size. With that said, even if the swell period is six seconds or more, a three-foot swell size is still going to make for a very rough day on the water.

On a calm day in Charleston, the swell size will be under two feet and the swell period will be 10 seconds or longer. These are the ideal days to go boating or kayaking. With that said, if you’re going kayaking and you’re not planning to stay inland, the swell isn’t really going to be a factor—instead, you’ll want to pay more attention to the tides and the wind.

When it comes to dealing with the swell, there isn’t really a whole lot of planning you can do other than trying to avoid unfavorable conditions. Generally, the swell will be less significant the farther inland you go. So, if you are thinking about heading to the Charleston Harbor or going to the beach and the swell looks unfavorable close to the coast, it is still worth checking out some alternate destinations upriver. There is plenty of boating and kayaking to be done on Charleston’s rivers—from the Wando, Cooper, and Ashly Rivers near the peninsula to the Stono, Wadmalaw, and North and South Edisto Rivers farther south.

3. Factoring the Wind Into Your Float Plan

Along with the tides and the swell, the third major environmental factor you’ll want to consider is the wind. When checking the wind, you don’t want to rely on your phone’s basic weather app—the wind can be (and usually is) much stronger on the water near the coast. You can use an app like Windy, or you can check the marine forecast from the National Weather Service (NWS).

How will the wind affect your boating or kayaking plans? For one thing, if it’s windy, you could find yourself dealing with wind waves in addition to the swell. This can make the water very choppy.

For another, going against the wind will require significantly more fuel (or physical effort if you are paddling). If you’re going with the wind on your way out, you will need to be careful to ensure that you are confident in your ability to get back.

Heavy winds or strong gusts can also just make for an uncomfortable day on the water. The wind can make it much colder; and, if you (or your passengers) are constantly dealing with spray, you might wish that you had stayed home. When combined with an unfavorable tide and swell, a forecast that calls for strong winds may be a sign that you should reschedule your trip for another day.

Here are a few additional tips for making informed decisions about dealing with the wind:

  • Check the Wind Forecast Along Your Route – Similar to the tides, you should check the wind forecast along your route. While it might be calm at the boat landing or your kayak put-in point, it could be much windier just a short distance away, and it could be very windy near the coast.
  • Check for Any Small Craft Advisories – Along with checking the forecast, you can also check for any small craft advisories. If the National Oceanic and Atmospheric Administration (NOAA) has issued a small craft advisory, you should stay home or choose an alternate destination.
  • Make Sure You Know Your Boat’s (and Your) Capabilities – Finally, if you are planning for the possibility of a headwind (either on your way out or on your way home), you should make sure you know your boat’s (and your) capabilities. You do not want to find yourself in a position where you are struggling to make progress or burning fuel at a rate that won’t get you home.
It is important to check the wind, swell, and tide when boating or kayaking in Charleston
Ideal conditions like these are fairly common around Charleston during the summer months. But, there are no guarantees, and it's always important to check before hitting the water.

FAQs: Dealing with Tides, Swell, and Wind When Boating or Kayaking in Charleston

How Can You Tell Which Way the Tide is Going?

There are two ways you can tell which way the tide is going. The first way is to use an app—there are plenty of options out there. Tides and Windy are two popular choices among boaters and kayakers in Charleston. Use the map feature to find the weather station or buoy closest to your current location —keeping in mind that the tide could still be slightly different exactly where you are. The second way is to shift your boat into neutral or stop paddling. Which way does the tide carry you? Depending on where you are, this will tell you whether the tide is going out or coming in.

When is the Swell Too Big to Go Boating?

For most casual boaters, a swell of three feet or more will make for an uncomfortable day on the water. This assumes you have a boat somewhere in the range of 18 to 22 feet in length. The larger your boat, the more swell it can comfortably handle. However, even if the swell size is smaller—in the range of one-and-a-half to two feet—a short swell period (in the range of four to five seconds) can make you wish you had stayed home.

When is the Swell Too Big to Go Kayaking?

For most casual kayakers, a swell of one-and-a-half to two feet can be more than they care to handle. This is especially true with a short period (in the range of four to five seconds). If you’re planning to kayak with a decent-size swell, you should be confident in your abilities, and you should have all of the safety equipment you need in case something goes wrong.

What Wind Speed is Too High for Kayaking?

Most kayakers will want to stay home (or choose an alternate route) if the wind speed is about 12 knots (14 miles per hour). Novice kayakers may feel uncomfortable with a wind speed in the range of 8 to 9 knots (roughly 9 to 10 miles per hour). If the wind is a factor, you will definitely want to check the tide and swell in addition to checking the weather forecast before hitting the water.

Is Swell Created By Wind?

Swell is created by several factors, including offshore winds. However, local wind also creates wind waves—which can run in the same direction, in the opposite direction, or at an angle to the swell. With this in mind, when planning a kayaking or boating trip in the Charleston area, it is important to check both the wind and the swell; and, in addition to checking the wind speed, you will want to check the wind direction as well.

When is Low Tide in Charleston?

Low tide varies from one day to the next. On average, the full tide cycle (from one low tide to the next) is 12 hours and 25 minutes in Charleston. This means that low tide shifts about 50 minutes later each day—though the specific timing of both high tide and low tide varies slightly from one location to the next. For example, low tide at the mouth of the North Edisto River (between Seabrook Island and Edisto Island) is about 15 minutes later than low tide in the Charleston Harbor.

How Big Are Charleston’s Tides?

Charleston’s tides average roughly six feet from high tide to low tide. However, on a king tide, high tide can be more than eight feet above low tide; and, on a spring tide, low tide can get below sea level. This means that Charleston’s tidal currents can be relatively strong; and, as a result, it is important to consider the tide when planning a kayaking trip or boat outing in Charleston.


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