By Mike Milne

For cruising power boaters, weather knowledge is essential and weather awareness is constant. Being able to sleep soundly at an anchorage or confidently head across a long open-water passage also means having solid 12- or 24-hour weather forecasts in hand and watching closely for changing weather.

For cruisers, checking forecasts is usually a morning and evening ritual. And because cell phone coverage in cruising areas can be iffy, most still rely on Coast Guard VHF radio forecasts.

Small-craft day boaters tend to be less vigilant, but knowing what weather is expected on any given day may be a deciding factor in whether to head out on the water at all. Being able to interpret forecasts and make better use of today’s weather tools will also mean more enjoyable fishing, tow sports or day cruising for cottage boaters.

On the water, knowing how to quickly interpret cloud, wind and temperature patterns will also be helpful. On the surface, a forecast may make it look like a poor day for boating. However, local knowledge of your boating area, closer analysis of your planned boating activities and keen observation of the skies and waters may deliver a different verdict.

Unlike cruisers, day boaters are likely to be operating in areas with good cell phone coverage, especially as it generally gets better every year. With the latest generation of smartphones, this means easy access to the Internet and an ever-growing list of free applications that put plenty of weather information at your fingertips.

Wind Alert app
Wind Alert App
Weather Network App
Weather Network App


I like The Weather Network app for a quick overview and a wide range of weather info. As you’d expect from any free application, it has some advertising, but in this case it’s only a small banner at the bottom of the display. The main screen give graphic forecasts and temperatures for your location for the next day and the following week, but a tap on the screen brings up more current details: wind speed and direction, temperature, pressure, humidity, visibility, ceiling, sunrise and sunset, and yesterday’s high and low temperatures. For boaters on smaller inland lakes, the information there is probably all they need.

WindAlert is another free app that gives a quick read of wind speed and direction. I set it to show knots and get a quick look at wind speeds in a variety of locations near me. Because I live on southern Georgian Bay but also have easy trailer-boat access to Lake Huron, I can quickly see whether near-shore boating will be more pleasant on the bay or the lake.

Apps are also available to decode the numerical MAFOR weather forecasts that are usually used by cruisers and broadcast continuously on VHF Coast Guard weather channels. So far, I have not found a free one. Nor is there an Environment Canada app that directly delivers easy-so-use marine weather.

That being said, it’s easy to bookmark an Environment Canada marine weather page for your area or the radar page for easy access. Like the “plain-language” versions of the MAFOR coded weather on the VHF channels, the marine weather on the Environment Canada’s Internet site is easy to understand and use. Boaters headed onto larger lakes and rivers or on the ocean should always get a full marine weather report.

World Radar is another free weather radar app that will show approaching rain or thunderstorms. MyRadar is a free app but provides only U.S. information. It’s a good resource for boaters in border areas, where weather often comes from the south or west. If you are considering buying an app, make sure to check carefully that it provides Canadian info.

No matter how they get their weather forecasts, day boaters need to know how to interpret them, based on where they are planning to spend the day on the water and what activities are on the agenda. Those operating in coastal areas also have to take tides into account in planning routes, as well as departure and arrival times.

Sun, temperature, cloud and UV intensity predictions will let boaters choose clothing and sunscreen. But wind and wave predictions are more significant, whether you’re planning to do some wakeboarding or water-skiing or just pulling up at a local beach or sandbar.

Environment Canada issues a Small Craft Advisory when wind in a local area is predicted to exceed 20 knots. High winds and the waves that come with them usually make fishing and tow sports increasingly problematic. But a boater with a sizeable craft operating in the lee of the land will be somewhat protected even in relatively high winds.

In judging how much wind they can handle and from what directions, boaters need experience and knowledge of their boat and their own ability. They also have to be realistic about their crew’s expectations and their real reason for being on the water.

It’s called pleasure boating because it’s done for enjoyment. So, even if you and your boat are capable of handling high wind and wave conditions, make sure your crew is up for the challenge as well.

Other Environment Canada marine weather warnings need less interpretation: Strong winds (20-33 knots); Gale-force winds (34-47 knots); Storm-force winds (48-63 knots) and Hurricane-force (64 knots plus). Tornado and waterspout warnings are also self-explanatory. A squall warning indicates a line of thunderstorms with wind gusts of 34 knots or more. If such weather is likely, stay at home or ashore.

Bell Cove, Nepture Island
Clouds over Bell Cove, Neptune Island

Forecasts can help boaters decide whether to go boating on any give day – or where, if there are choices – but they still need to know what to watch for on the water as the day proceeds. Weather does not always unfold as forecast and savvy boaters must be able to “read” the weather from wind, water and the sky.

In Canada (except the far north), the prevailing winds come from the west, but that can change depending on weather systems operating in any locale. These weather systems are largely controlled by the movement of warm and cold air masses, which help to create high and low pressure systems. In the northern hemisphere, winds around high pressure systems move clockwise and outward from the system, but winds around low pressure systems move counterclockwise and inward.

While the movement and clash of those air masses create changing weather, those changes are always signalled by changes in the sky – in the types of clouds that are visible and how and where they are moving. So boaters should watch clouds for clues to changing weather.

There are four basic cloud types that also combine to formed mixed types:

  • Cirrus: high-level wispy clouds that usually mean fair weather, but if massing together can mean a change within 24 hours
  • Cumulus: low-level fluffy white or off-white clouds that usually accompany good weather;
  • Stratus: layered clouds that can bring light rain or drizzle if they spread across the sky; and
  • Nimbus: dark puffy-looking classic rain-clouds.

There are also cirrocumulus clouds that form what’s known as a “mackerel sky,” which looks like fish scales and usually means approaching storms. Alto-cumulus or high cumulus clouds on humid mornings usually mean rain is on its way, while dark cumulonimbus clouds means rain is imminent. When cumulonimbus clouds grow tall and dark, they can also form anvil-shaped clouds that bring extreme weather such as rain, hail or thunderstorms. Squalls along storm fronts can also bring high winds.

Generally speaking, higher clouds indicate what weather is moving in. If they are spread out, white and wispy, the weather will usually be fine. But if they start to mass, it could mean a cold front is coming, especially if cirrocumulus or alto-cumulus clouds form a “mackerel sky.”

Warm fronts are generally preceded by cirrus clouds, then cirrostratus and high-layered altostratus clouds. Thicker nimbostratus clouds follow and usually bring rain.

If you’re on the water and think a storm or squall may be coming your way, it’s sometimes a good idea to take a look at the weather radar, which will show rain and where it’s already falling. With a bookmarked web page or an app on your phone, it’s easy.

If they decide to take shelter and wait out a storm, boaters can check the clouds to see if they are moving or dispersing, but can also check the radar to confirm whether more rain or squalls are coming and where.

While boaters, especially those on big waters, tend to watch closely for bad weather, it’s also good to remember that much of Canada’s summer weather is lovely. Slow-moving air masses and pressure systems improve the chance of that. A slow-moving high-pressure system just south of the Great Lakes region, for example, can bring mild weather, with high cirrus or altocumulus clouds and a few low patches of cumulus clouds.

Boaters should still check weather forecasts to see what’s coming later, but when it’s a lovely day to go boating, most boaters can tell by a quick look at the sky. Knowing how to recognize the signs of changing weather and having easy access to professional forecasts will give them added confidence to head onto the water.

This article is featured in the Spring 2014 issue of Boats&Places.