Calgary's sudden switch to cold and snow may signal a chillier-than-usual winter ahead, a senior climatologist says.

"​Last year was a really balmy, record-setting November. This year it's going to be the opposite," Environment Canada's David Phillips told the Calgary Eyeopener on Tuesday morning.

Cold, snowy weather is expected starting in November, but what's unusual has been the lead-up to the snap, he said.

Calgarians saw temperatures change from a comfortable 17 C on Oct. 28 to snowfall warnings and then a bristling –18 C a week later on Nov. 4, the national weather agency's data shows.

'You've been spoiled'

This comes after seven months of warmer-than-normal temperatures, including the warmest summer in Calgary since records began in 1881, Phillips said.

"See, you've been spoiled," he said. "Really, from April right through to October, temperatures were a little on the mild side — and then all of a sudden, you change the calendar and you change the weather."

Right now, Calgary is being affected by a weak La Nina cycle, which is a cold weather event. Westward winds carry warm water on the top of the Pacific Ocean further south, Environment Canada explains on its website. That allows cold water to rise to the surface, which gets pushed north by strong easterly winds.

The cycle typically brings Canada colder winters.

'Little teasers' of snow

The entire winter shouldn't be like this past week in Calgary, Phillips said, but more of a back-and-forth between cold, snow and melting, with "something for everyone."

Skiers will be happy to hear more snow is on the way.

"These are not Paul Bunyan snowfalls that will come up this week," Phillips said. "These are kind of little teasers, reminding you, if you haven't got your snow tires on, think about it."

By Sunday, temperatures may be up to four degrees higher than average for a few days, he said.

With files from the Calgary Eyeopener