Here's a look at all the extreme cold days since the 1970s

The 1970s were a momentous time in Montreal.  The city was gripped by the October Crisis, the Summer Olympics, and the Grand Prix moved to its current home on Notre-Dame Island.

It also experienced the craziest weather it had seen: a record snowfall, the highest temperature ever recorded (36.7 C in 1975), and the longest stretch of extremely cold days on record. 

In 1970, there were no fewer than 34 days where the mercury dropped below -20C.

Not only that, there were eight cold snaps with consecutive glacial temperatures. The rest of that decade wasn't much better.

It makes the current seven-day forecast seem rather tame.

If Montreal has dealt with colder days at longer stretches in the past, why does it feel like we're talking more about it this time?

Dave Phillips, senior climatologist at Environment Canada, thinks that being the first cold snap of this winter, there's a surprise element to it.

"By February and March, we're used to it. We figured out how to survive in these conditions," he told CBC's Homerun.

Also, it's been a while since we felt this frigid. "This is colder than any moment we had last year," he said.

Below is a chart of all the days since 1970 where the minimum temperature dropped under -20C. Why -20? 

It's an arbitrary threshold, but psychologically, it just feels like really, really cold weather.