Understanding the Marine Weather Forecast

What Does the Marine Weather Forecast Tell You?

A marine weather forecast is so important for yachters and boaters (and their guests) to understand. 

As all boaters know, a sudden change in weather patterns can not just interrupt a day at sea, but it can put your vessel and your guests in danger. Knowing how to interpret the marine weather forecast, both before you set sail and while you are on the water, is vital to avoiding any potentially hazardous weather situations.

Marine Weather Forecasts are different to general weather forecasts, as the predictions include wind and wave information. This information can help you decide if it is safe to set out on your planned boating trip.

What is the Marine Weather Forecast?


In Canada, the Marine Weather Forecast is published by Environment Canada, using observations from ships, weather satellites, weather buoys and lighthouses.

There are three main forecast bulletins issued by Environment Canada, covering a five-day period, which are updated multiple times each day.

  • Regular Marine Forecast

This forecast is for the coming 48 hours and includes information about:

  • Wind speed in knots
  • Wind direction
  • Weather conditions
  • Precipitation
  • Visibility (included if less than 1 nautical mile)
  • Moderate or severe freezing spray expectations
  • Air temperatures if below 0oC
  • Extended Marine Forecast

This forecast is issued for days 3 to 5 and is intended for long term planning purposes. The extended forecast only details anticipated wind conditions.

  • Wave Height Forecast

Issued for the coming 48-hour period, this forecast details the anticipated wave height in meters or whether waters are covered in ice.

Additional information is also published as:

  • Technical Marine Synopses: Gives a brief overview of the main weather systems in the area.
  • Marine Weather Statement: Used in support of the regular marine forecast to provide more detail when significant or hazardous conditions or weather warnings are predicted.

Localized warnings and watches are also issued if one of the following significant conditions is expected:

  • Tornado
  • Gale
  • Squall (Gusts of 34 knots or higher plus thunder)
  • Waterspout
  • High water levels

As well as being found on the Environment Canada website, marine weather forecasts are also continuously broadcast on VHF radio channel 16 by the Canadian Coast guard.

How to Use the Marine Forecast to Determine if it is Safe to Sail

Reading or listening to the boating weather forecast should always be part of your pre-trip checklist, but that is only useful if you know how to interpret the information within it. 

Here are some key items to be aware of:

Wind: Forecasts state the wind direction using compass descriptions and give the wind speed as an average or a range. When gusts are predicted this indicates winds will increase by 10 or more knots for short durations. As a guide, whitecaps can start to form when winds are over 10 knots.

Waves: Waves will be affected by wind speed and direction as well as tidal currents. Canadian wave forecasts only describe the wave swell which is the distance from crest to trough. When higher swells are combined with short interval times (waves coming closer together) due to high winds, waves can be larger and cause a hazard or danger to smaller vessels.

Weather conditions: Watch forecasts for extreme conditions such as heavy rain, low visibility due to fog and high-water levels as these could obstruct your vision or cover obstacles that are usually above water level. If you are caught on the water in these conditions, ensure you use your radar if your boat is equipped with it, to detect other vessels or objects. 

Ultimately, a combination of the marine forecast, your own observations and experience and the capabilities of your vessel will tell you whether it is safe for you to take your boat onto the ocean. 

Remember to continue to listen to the boating weather forecast while you are on the water. Additional updates will be broadcast if a significant change to predicted weather is expected to occur.

What Should I Do If I Get Caught in Bad Weather at Sea?

Regardless of predictions, the weather can still change suddenly and even the most careful boater can find themselves in an unexpected situation. To avoid extreme weather changes, keep an eye on the horizon at all times to ensure you see major storm systems before they reach you.

 If you do get caught in bad weather on the ocean, remember the following tips:

  • Reduce your speed to as low as you can while still making headway
  • Ensure everyone aboard is wearing a personal floatation device
  • Turn on your running lights
  • Head into large waves at a 45-degree angle
  • Go to the nearest anchorage or marina
  • If you can’t make headway or your engine fails deploy your anchor and make a distress call

Also see our guide to safe boating in poor visibility for more tips on staying safe when visibility is restricted by bad weather or strong winds make it difficult to maneuver your boat.

Tools and Equipment for Weather Monitoring

Keeping track of the marine weather forecast has never been easier thanks to the development of a number of high-tech tools.

A number of smartphone apps are now available for boaters which give up-to-date marine forecasts for the area you are in. This can be particularly useful if you are boating in international waters.

In addition, modern barometers, meters and wireless weather stations can be added to your yacht to ensure a detailed forecast and accurate weather predictions are always available when you are on board.

Get a Yacht Equipped for Weather Monitoring at Van Isle Marina

At Van Isle Marina, our friendly staff are always on hand to give advice on local marine weather conditions. If your original destination is off-limits due to incoming conditions, our staff will gladly make alternative suggestions so you can still enjoy your day. How about lunch at the Seaglass Waterfront Grill while you wait for the weather to clear?

Looking for a new yacht that has the latest weather tracking technology already installed? Our yacht broker will work with you to find a vessel that ticks all your boxes and has the equipment to provide you with a marine weather forecast too. Contact us today for an appointment with our yacht broker.