Captain’s Blog

Here’s What Every Boater Needs to Know About Weather

There’s a line from a Jimmy Buffet song about “going where the weather suits my clothes”.  I’ve adapted that to my boating life to be “going when the weather suits my wife”!   I made the conscious decision to go out on the water to have fun, not to prove anything.  My experiences with really bad weather have proven I don’t enjoy it.  Even though I know my boat can handle it.   Having cruised almost 5000 miles in the past 4 years, only a few hours were spent in conditions that were anything approaching “uncomfortable”.  It just takes information and planning. This includes some key things every boater needs to know about weather.

Boating weather

Some Misconceptions About Boating Weather 

A lot of people focus on the wind as the biggest concern when it comes to boating weather.  And while you can’t ignore the wind, for most boaters, that’s not what gets them in trouble.  It’s the size, periodicity, and direction of the waves that causes most of the issues.  Yes, wind creates waves, but not equally across all bodies of water.  For example, 25 knots of wind that has a fetch (distance the wind can blow without obstructions) of 20 miles is going to create much bigger waves than 25 knots of wind that has a fetch of 1 mile.  Likewise, if that 25 knots of wind is from directly behind me, it’s not as much concern as the same 25 knots of wind on the beam. Currents play a factor too.  25 knots of wind running with the current is going to produce smaller waves than 25 knots of wind with an opposing current.

Waves Are the Real Worry for Boaters

In most weather forecasts, waves will be indicated as two different components:  swell, and wind waves.  These two components are fully independent and can come from completely different directions and be of different sizes and periodicity.  For example, it would not be that unusual in Southern California to have the “Pacific rollers” coming out of the west/northwest, with wind waves coming out of the south.

In looking at wave action, it’s generally not the size of the wave that concerns me, it’s the periodicity, or the spacing between the waves.  I will go out in 10-foot swells spaced at 20 seconds all day long, but 5-foot waves at 4 seconds might keep me tied up in my slip.   The gentle rolling long period swells are fun – elevator up, elevator down.  No sweat.  The pounding of closely spaced wind waves makes for an uncomfortable (and dangerous in the wrong boat) ride.   My rule of thumb is to have the wave spacing at a minimum of 1.5 times the wave height.  If the waves are 4 feet, I like to have them at least 6 seconds apart, and I would be happier with 8.

Knowing what kind of waves your boat can handle is another decision point.  A small pram with an outboard engine might head for the beach when the wind waves get above 1 foot, but a heavy ocean cruiser might be perfectly comfortable with 6 footers all day long.   It’s both crew comfort level and the stability of the vessel.  Every skipper has to make their own assessment about what his/her vessel and his/her crew can handle (and enjoy) safely.

Get Your Boating Weather Information in Advance Calm Ocean for Boating

So, where do you get the best weather info?  I’m glad you asked!  First of all, focus on sources of marine weather.  Your typical weather channel forecast is not going to give you the weather info you need about wind, waves, fog and changing conditions out on the water.   The National Oceanic and Atmospheric Administration (NOAA) is the prime source for most marine weather information.  Even many of the great marine weather apps pull their data from NOAA, and just display it in a more user-friendly format.   NOAA marine weather, provided by the National Data Buoy Center (NDBC) provides regularly updated forecasts extending out 5 days for all coastal areas.  Click here for the link to the Southern California forecast: https://www.ndbc.noaa.gov/data/Forecasts/FZUS56.KLOX.html    You will note that the forecast is broken up into different regions throughout Southern California, covering both coastal and offshore areas.

For more graphical and user- friendly forecast data, there are a number of free websites and apps out there.  They’ll provide just about everything you need to know, including wind, waves, pressure systems, etc.  Some of my favorites are:

Personally, I never rely on a single source.  I look at NOAA and one or more of the sites above.  If they all tell me the same thing, I’m good to go.  Or am I?

Let’s not forget one of the best weather tools around:  Your eyes.  That’s right, take a look outside.  Does what you see correspond to what the forecasts are saying?  There are things called “microclimates”, which can cause the weather that you experience in a specific location to be different from what has been forecast for the general area.

Weather Routing Services

Yes, there are things every boater needs to know about weather.  But, if you’re really serious about weather, and planning to take a long passage, you might want to think about having a professional on your side.  For a fairly nominal fee, professional weather routers tell you exactly when and where to go on a trip from point A to point B.  Even with all the great free weather sources out there, I still use a weather routing service if I’m going a long distance up/down the coast.  It’s cheap insurance and they can even update you on changing conditions along the way.  Two of my favorites are WRI (www.wriwx.com ) and Commanders (https://www.commandersweather.com/) but there are undoubtedly many other options.

Weather forecasting has come a long way in the past 10 – 15 years, and with all the great data available to you for free, there’s no reason to get caught by surprise.  So, find your favorite sources and become religious about checking them before you leave the marina and you’ll make your boating experience and those of your friends and family that much more enjoyable.

Be safe out there!

Cap’n Dave