ATSC 113 Weather for Sailing, Flying & Snow Sports

Marine Weather Forecasts

Learning Goal 11a: Access the short-term and extended marine forecast for a given location.

Students: For the final exam, just be aware of the main sources of marine weather info:

  • Environment and Climate Change Canada (ECCC),
  • NOAA Ocean Prediction Center (OPC),
  • Continuous Maring Broadcasts (CMB),
  • Weather Radio

and what types of info they provide.  Do not memorize frequencies, phone numbers, channels, etc.

Environment & Climate Change Canada (ECCC)

Imagine you’re planning a trip to Saltspring Island for the long weekend. First, you want to know what the weather is going to look like. There are numerous resources available for forecasting the weather. For recreational cruising on Canada’s coastlines, the marine forecast provided by Environment & Climate Change Canada (ECCC) is a good place to start. It can be found here:

The ECCC forecast provides detailed forecast information for the next 48 hours and a general forecast for the three days thereafter. The page starts by listing the regions with weather warnings in effect, then provides links to the remaining weather conditions, with links to other forecasts (e.g. radar, satellite, extended forecasts), weather alerts (e.g. hurricanes, public alerts), and weather resources (e.g. astronomy, historical data).

Now, go to the ECCC (linked above). For a trip to Saltspring Island, your region of interest will be the Pacific – South Coast. First, check to see if there are any warnings in effect in your region and then proceed to the next page where the region is broken down into areas. This page is the same as the previous one, but with a narrower spatial scale. For Saltspring, you would select ‘Strait of Georgia – south of Nanaimo’. If there is a warning in effect in your area, it will be bolded and in red across the top of your areas weather forecast. For example, it might read “STRONG WIND WARNING IN EFFECT” with a summary of when the warning starts and when it is predicted to end (see image below for an example). Your extended forecast will also be provided and usually extends 4 days ahead (see 11b for more information on Weather Warnings ).

sog weather warning

The focus of the marine forecast is wind direction and speed; however, some locations will also have wave forecasts providing sea height in meters. Storms or fog are also included in forecasts. Let’s take a look at the Environment Canada’s forecast for the Strait of Georgia south of Nanaimo:

Sog weather forecast

You have northwesterly winds between 10 and 20 knots forecast for the entire weekend. These are perfect wind conditions for a casual sail across to the Gulf Islands! Conditions change however, and it is important to monitor the weather while you’re on the water.

NOAA Ocean Prediction Center (OPC)

For voyages across the Pacific Ocean, a good place to start for an overview of conditions is the Pacific Analysis weather map produced by the Ocean Prediction Center (OPC) of the US National Oceanic and Atmospheric Administratino (NOAA).  You can find it at  .

weather map

Example of weather map for the eastern North Pacific Ocean. Source: 

We will learn how to read these weather maps in Learning Goal 11c.  They show pressure, winds, fronts, lows, highs, typhoons, troughs of low pressure (TROF), and weather warnings.

Additional sources of info across the Pacific are satellite images.  These will be discussed in more detail in Learning Goal 11d.  They show clouds, from which we can infer locations of fronts, highs, and lows.

Canadian Coast Guard Continuous Marine Broadcast (CMB)

The ECCC weather forecast for the entire Pacific region is recorded by the Canadian Coast Guard and broadcast as a continuous loop throughout the day on various radio frequencies. This is called the Continuous Marine Broadcast (CMB). The forecast is updated at 04:00, 10:30, 16:00, and 21:30. The loop is also reset to the latest forecast at these times. The broadcast cycles through the areas listed by ECCC and so you have to be careful to listen for yours, otherwise you have to wait through an entire loop before the forecast for your region is broadcast again.

Sailors can take advantage of the public weather alert system known as the Weather Radio.  The Canadian Weather Radio channels are in the table below.

Public Alert
(Weather Radio)
WX1 162.550 39B 7
WX2 162.400 36B 1
WX3 162.475 97B 4
WX4 162.425 96B 2
WX5 162.450 37B 3
WX6 162.500 38B 5
WX7 162.525 98B 6
WX8 161.650 21B
WX9 161.775 83B
WX10 163.275 113B

You can access the CBM via these VHF weather radio channels while out on the water. Channels 1-7 are broadcast in both English and French. Different areas use different frequencies, so you have to know which frequency or channel pertains to the waters you are in. 

For example, the Vancouver area forecast is on channel 7 (frequency 162.550 MHz) and Victoria is on channel 1 (frequency 162.400 MHz).

In addition to the weather, the Canadian Coast Guard CMB also tells you:

  • Marine Communications and Traffic Service Centre Identification (MCTS, who is providing the forecast)
  • Distress and Urgency priority information (information regarding the details of on-going marine incidents is broadcast to other mariners)
  • Ice formation
  • Notices to shipping (announcing any hazards to navigation)
  • Weekly mean water levels
You can also listen to the same audio recordings by telephone:
Served from the Prince Rupert MCTS Centre:
  • Continuous Marine Broadcast (CMB) North & Central BC Coast: 250-624-9009 
  • Continuous Marine Broadcast (CMB) South Coast & Pacific side of Vancouver Island: 250-726-3415
Served from the Victoria MCTS Centre, for the Georgia Strait and Vancouver and Victoria areas:
  • Continuous Marine Broadcast (CMB) Mount Helmcken: 250-363-6880
  • Continuous Marine Broadcast (CMB) Bowen Island/Mount Parke: 250-363-6492
  • Continuous Marine Broadcast (CMB) Bowen Island/Mount Parke: 604-666-3655
  • Continuous Marine Broadcast (CMB) Mid Island Area: 250-339-0748
  • Continuous Marine Broadcast (CMB) North Island Area: 250-974-5305

Other Weather Resources

Environment Canada’s Marine Weather Forecast should be your first stop for weather information. However, there are several alternative weather resources available to you. The more you know about the conditions you will be sailing in, the better, so look around online, review multiple weather forecasts, read the forums, and make informed decisions. Here are a just a few to get you started:

Additional Resources: (non-required material)

Environment Canada’s Marine Forecast and Warnings for Canada:

Guide to Environment Canada Marine Weather Forecasts:


Keywords: Environment & Climate Change Canada (ECCC), warning, Continuous Marine Broadcast (CMB), VHF radio, weather radio

Image credits: are given near the images.