How Does The Ocean Affect Weather?

Check Canada’s marine forecasts before you travel to coastal regions, because the ocean’s stored heat and moisture directly control fog, wind, and storm tracks. The ocean moderates temperatures and supplies the humidity that fuels precipitation, making it the single most important driver of Canada’s variable weather.

How does ocean temperature change the air above it?

Warm ocean water heats the air from below, causing it to rise and draw in moisture. This rising air forms clouds and often rain – a process that gives British Columbia its famously wet winters. Cold ocean water, by contrast, stabilises the air, suppressing clouds and keeping coastal areas drier and cooler in summer. The temperature difference between ocean and land also creates sea breezes and coastal fog, especially along the Atlantic and Pacific shores.

Why does the Pacific Ocean affect Canada more than the Atlantic?

The Pacific is larger and its surface currents, like the Kuroshio, carry warm water northward. This feeds the persistent low-pressure systems that bring rain to Vancouver Island and the mainland. The Atlantic, dominated by the cold Labrador Current, chills the air over Newfoundland and Labrador, leading to frequent fog and cooler summers. The contrast between these two ocean influences explains why Vancouver’s weather is mild and wet while St. John’s is often foggy and raw.