Why the sun shines more on the prairies than the rest of Canada

CBC Alberta and Saskatchewan have teamed up on a new pilot series on weather and climate change on the prairies. Meteorologist Christy Climenhaga will bring her expert voice to the conversation to help explain weather phenomena and climate change and how it affects everyday life.

If you want to catch some rays in Canada, your best bet is to go to the prairies.

Southern Saskatchewan and Alberta lead the country in sunshine, with many communities in these provinces watching more than 2,400 hours annually, according to Environment and Climate Change Canada. To put it in perspective, some areas along the Pacific coast see only 1,200 to 1,400 hours of bright sunshine a year.

The two provinces enjoy more hours of sunshine because the prairie climate is simply drier.

Areas close to large bodies of water get much more cloud cover and precipitation with all the humid air, such as the atmospheric river event we saw recently in BC.

Edmonton sees an average of 446 millimeters of rainfall per year, with Calgary close by with 419 millimeters. Regina and Saskatoon get 390 millimeters and 354 millimeters, respectively.

These numbers pale in comparison to Vancouver, where it is normal to see 1,189 millimeters of rainfall in a year.

Without the consistent cloud cover and wet weather, the prairies get a lot of sunshine.

That abundance of solar is the reason why the prairies see a significant boost in a rapidly evolving solar energy industry.

A number of major solar energy projects are already underway to meet this potential, including the Travers Solar Project in Lomond, Alta., And a proposed solar farm near Edmonton International Airport.

SE | Meteorologist Christy Climenhaga explains what lies behind the sunny prairie skies:

What makes Alberta and Saskatchewan the sunniest provinces

Meteorologist Christy Climenhaga explains why some cities in southern Alberta and Saskatchewan benefit from more than 2,400 hours of sunny weather each year. 1:27

Rain shadow effect

There are a number of reasons why the prairies are so dry, but in the center, as in real estate, it’s about location.

The western prairies are far from any significant source of moisture. The nearest source is the Pacific Ocean, but that moisture has something of a journey to get to Alberta and Saskatchewan.

Although moisture from the Pacific Ocean can reach the prairies, it must pass a major obstacle. That brings us to the second reason for the sunny weather of the prairies.

The western prairies sit in what is called a rain shadow.

As the air moves over the mountains, it loses much of its moisture. (CBC News)

Looking at Canada’s topography, we see that Alberta has the Coast Mountains and Rocky Mountains to the west and the plains to the east. Moisture-filled air coming from the Pacific Ocean hits these mountain ranges and rises. When it rises, it cools and we get condensation and rain or snow.

By the time the air falls on the leeward side of Alberta, it is depleted of moisture.

Now, of course, Alberta and Saskatchewan are getting rain, but the rainfall trends on the prairies are different from other areas of Canada, bringing us to the third reason for so much sunshine.

Fast-moving storms

The jet stream – the narrow band of fast-moving air in the upper atmosphere that controls our weather systems – often leaves the prairies with a large ridge of high pressure.

Air in that high pressure drops and usually means little or no cloud cover, giving Alberta and Saskatchewan the beautiful blue skies they are known for.

When storms occur, they move quickly. Prairie weather systems such as Alberta cliffs or low tides in Colorado can generate a lot of water, but then go on the road within a day or two.

The other major summer storms on the prairies are convective thunderstorms, which usually come in the evening after a relatively sunny day, so even though we get the impressive cloud formations, most of the day still counts as sunny.

Although we can get a lot of rain and impressive cloud formations during thunderstorms, these storms often occur later after a sunny day. (Posted by Matt Melnyk)

How can climate change affect sunshine?

When our climate warms, you might think, “OK more evaporation, more moisture in the air, that means more clouds and less sun.”

However, that may not be the case.

When our air is heated, our relationship to relative humidity also changes.

So while we may have more water vapor in the air because the air itself is warmer, the relative humidity may be comparable to what it is now.

That means we can still have the same amount of cloud cover, but when these storms hit, we can see more rainfall because there is more water present.

So more rain or snow, but the same amount of sun, even though it may sound counterintuitive.

Our planet is changing. It’s our journalism too. This story is part of a CBC News initiative titled Our changing planet to show and explain the effects of climate change and what is being done about them.

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