The 180

Has spring already sprung? That depends on your definition

Spring starts at the equinox, right? Not if you ask a meteorologist.
Bright green shoots break through the mulch at a garden in Windsor, Ontario, in late February. (Dan Taekema/CBC)

Spring starts on March 1st. 

That may be a little hard to believe, but if you're a meteorologist like Ryan Snoddon, it makes a lot of sense. That's because people in his field use a system of "meteorological seasons."

"It makes it easy for stats, and for comparing seasons," says Snoddon. "With astronomical spring, summer and fall, it's based on the position of the Earth in relation to the sun, we've got that extra fourth year where we have the leap year, it's inexact." 

Meteorologist Ryan Snoddon says his favourite sign of spring is melting piles of snow - or maybe melting snowmen, like this one in B.C. (David Horemans/CBC)

Because the equinoxes and solstices aren't on the same date each year, the seasons they dictate, known as "astronomical seasons," aren't the same length every year. That means, if you're trying to compare stats like snowfall accumulation year-over-year, you won't have an accurate comparison. 

So instead, meteorologists separate the seasons into chunks of three months. Spring, for example, starts March 1st and ends May 31. 

The meteorological seasons

Spring: March, April, May
Summer: June, July, August
Fall: September, October, November
Winter: December, January, February


But in parts of Canada, spring doesn't start until April, or even May! 

Snoddon says it helps to think of spring as a season of transition. If you do that, it makes sense to think of March 1st as the beginning of spring: "March is a month when we can see big, record-breaking warmth temperatures. It's also a month where we can have a big blizzard coming through. That's a transition month to me, that's not winter." 

Perhaps the most popular sign of spring: the crocus. (Darren Bernhardt/CBC)

Have your say on the seasons

Which definition makes most sense to you? Do you like the astronomical system, or the meteorological one? 

Which sign do you look for to mark the arrival of spring? Is it when snow piles start shrinking, when flowers start blooming, or is it something else altogether? Leave your thoughts in the comment section below, or send an email to the180@cbc.ca