TORONTO -- Saturday marked the first official day of spring, and for much of the country, it really feels like it.

"It's a gorgeous day, not a puff of cloud in the sky-blue skies," Environment Canada senior climatologist Dave Phillips told CTV News Channel from his home in Barrie, Ont. on Sunday.

In Toronto, Montreal, Ottawa, Fredericton and Halifax, Environment Canada says highs in the double digits up to 16 C are expected this week.​ Collingwood, Ont., which was Canada's warmest community as of Sunday afternoon, could see temperatures reach 18 C on Monday.

"We've had for the last couple of weeks kind of almost a preliminary look to spring. It's been mild, some actually very record warm temperatures on the prairies and lots of sunshine in Eastern Canada," said Phillips.

"Everybody from coast to coast to coast, this is the first full day of spring, and there is not a weather warning, anywhere in the country. Nature is shining on us at this time."

Phillips expects this spring to be milder than normal for much of the country from Saskatchewan to the Maritimes. But despite the warm weather, he warns that Canadians should wait until after April before putting away their jackets.

"I always say, 'Until April's dead, change not a thread'," said Phillips.

Even though spring has officially started, Canadians can expect winter weather to likely have at least one last hurrah in most parts of the country.

"(The) reality is that 10 to 30 per cent of our annual snowfall occurs after the first day of spring. There are very few places in Canada that have ever had spring without some snow, and even some cold, but you know when that happens, it's usually a one- or two-day wonder and then you're back into the warm air," said Phillips.

Nonetheless, Phillips said he feels optimistic about this spring.

"There's so much optimism across the country, the vaccines have trickled and now they're flooding. This is a season of rebirth and growth and I can tell by the people, the way they are walking and the smiles on their faces, there's never been more optimism about this spring than any other year I can remember."