How much colder was Yellowknife before? We checked the data

Whenever there’s a cold snap in Yellowknife, someone always tells you: this is nothing. Back in their day, it was this cold allll the time.

Was it, though? We checked Yellowknife’s temperature records to find out. Those records stretch back to 1942, although there’s a little more information from the early 1950s onward.

The bottom line is they’re right. Yellowknife is warmer now than it would have felt during the childhoods of people who grew up here in the 1960s and 1970s.

But we still have occasional years that are as cold, on average, as it was half a century ago or more.

They’re just not as common, and the cold is rarely as prolonged as it once was.

For example, 2020’s mean temperature – the average for the whole year – was -4.9C. Most years since 1970 have been warmer than that, and even 1954 was a marginally warmer -4.7C.

But 2015, 2016 and 2017 were all warmer than -3C, which had never happened even twice in a row before 1998.

At this point, it’s worth noting that temperature data reliability can change over time, as can the techniques and technology used to collect it.

We’re using data from various Environment and Climate Change Canada sources, as compiled by WeatherStats. The raw data can be downloaded if you’d like to inspect it yourself.

Let’s start with how Yellowknife’s temperature has changed since the 1950s.

The simple colour bars above tell a story: the darker the blue, the colder that year was. The bars to the left, in the 1950s and 1960s, are clearly colder – in general – than the more recent bars on the right.

The past few years have been moderately cold. Yet we virtually never experience years colder than -5C these days, which is a change from decades past.

Anyone who’s read a newspaper in the past 30 years won’t be surprised to learn Yellowknife is warmer than it was.

That tallies with what we know about much broader patterns of climate change across the North, Canada, and the globe.

Here’s how Yellowknife’s temperature change compares to three other Canadian cities. In each example, the pattern is similar.

The charts above take mean temperature data for the entire year, meaning they can’t tell you if a winter was particularly cold or a summer particularly warm. That data is merged into one overall figure for the year.

Let’s now look at the coldest temperature Yellowknife has recorded each year since 1954.

The pattern is pretty similar to the one above, but it’s not quite identical.

It’s clear that Yellowknife’s very coldest days have lost a few degrees since the 1980s. (All figures on this page are raw temperature, without wind chill.)

In fact, 2021 is a rarity in having reached -45C.

Yellowknife had not done so since 2008, a year that contained a memorable January cold snap.

The city’s all-time record without wind chill is -51.2C, set in 1947. Yellowknife has not seen -50C since.

Saturday, February 6, which registered a low of -45.4C, was Yellowknife’s 73rd-coldest day on record. But to give you an idea of how much warmer things now are, Saturday was the third-coldest Yellowknife day since 2000.

Speaking of cold snaps, let’s look at some.

For the purposes of this article, we’re calling a cold snap a period of seven or more consecutive days during which Yellowknife’s temperature did not once exceed -30C.

As the chart shows, that kind of prolonged cold was common in the 1960s, 1970s and into the 1980s. Even 1994 managed to crank out a 19-day stretch of bitter cold.

But those cold snaps all but disappeared in the past decade. (Full disclosure: There is a week-long period over Christmas 2013 that only just misses the list – one day had the temerity to sneak above -30C.)

Late 2019 and early 2020 actually marked a miniature return to form for the city. Back-to-back stretches of brutally cold weather turned up for the first time in decades.

These past few days aren’t likely to make the list. Yellowknife is due to be back above -30C by Tuesday.

Which brings us on to how 2021 looks so far. Is it actually that cold?

Not really, no. January is almost always Yellowknife’s coldest month but this one was significantly warmer than usual.

The start of February is a different story, though. Take a look.

Even going back decades, this February’s dip in temperature is a little unusual.

Only nine times has Yellowknife been colder later in February than it was on February 6 this year.

So maybe this past weekend, for once, the people telling you it was colder in their day were wrong.

But normally, they’re right.