Toronto finally got its first taste of the deep freeze this season on Thursday, a chill that brought yet another weather record attributed to an unseasonably mild winter.

The city's dip down to -6 C on Thursday marked the first time the mercury plunged to this level so far this winter, marking the latest arrival for a -6 day since record-keeping began in 1840.

For at least 184 years of records, Toronto has not waited this long in a season for temperatures to hit these lows.

🥇Today is #Toronto's first -6°C of the season, which is the latest on record. Typical first is December 7. Record earliest is Oct 21, 1845; latest Jan 4, 2024. #YyzWx #TOWx #YYZ #ONWx pic.twitter.com/kf4mOBG4hX

— Toronto Weather Records🌤 (@YYZ_Weather) January 4, 2024

Weather historian Rolf Campbell tracked statistics on the latest first -6 C days dating back to the start of weather record-keeping in 1840, January 4, 2024, marking the longest it took in a season for temps to drop so low.

All of the top three latest arrivals of -6 temps occurred during the first days of January within the last several years. In contrast, all of the top ten earliest arrivals of -6 temps were recorded in the period spanning from the 1840s to the 1930s.

Campbell recorded similar stats for the first arrival of -5 C weather of the year, where Thursday, January 4, also took the top spot.

🥇Today is #Toronto's first -5°C of the season, which is the latest on record. Typical first is November 25. Record earliest is Oct 11, 1855; latest Jan 4, 2024. #YyzWx #TOWx #YYZ #ONWx pic.twitter.com/IvmRenEpbD

— Toronto Weather Records🌤 (@YYZ_Weather) January 4, 2024

While I am no climatologist, it seems notable that this period of longer, harsher winters seemed to end right around the time of mass automobile adoption in North America.

It's also worth noting that this year's unseasonably mild winter is mainly being attributed to a particularly potent El Niño, expected to bring mild conditions for much of the season.

However, it's almost impossible to ignore the worrying trends after a 2023 marked by several concerning weather-related milestones, including seeing the warmest year on record worldwide, unprecedented wildfires and general climate chaos.

Even before the winter arrived, many northern Ontario First Nations expressed concern about the viability of ice roads that serve as important community lifelines amid mounting climate change.

Closer to home, the Great Lakes — which typically see approximately 55 per cent ice coverage by early January — had experienced less than half a per cent overall freezing before Thursday's chill arrived.

Wow - The Great Lakes typically have an ice coverage of 55% during the winter months, causing at least half of their surfaces to freeze. As of yesterday, they had a combined ice cover of just 0.2%. Lake Superior 0.5%, Lake Michigan 0%, Lake Huron 0%, Lake Erie 0%, Lake Ontario 0% pic.twitter.com/B8ocf1zMYR

— Peter Dynes (@PGDynes) January 1, 2024

In Toronto, warmer weather has resulted in popular skating rinks being reduced to murky pools of slush, the bleakest Christmas in recent memory, and multiple broken heat records at a time of year when the city is typically inundated with snow.