Another warm January in the books

2024 is off to a warm start with "milder than normal" January temperatures that are expected to continue throughout February, Environment Canada says. 

Ottawa's average temperature last month was about –6 C, around four degrees warmer than the city's January average.

It comes on the heels of a mild December and a warm January 2023, said Geoff Coulson, a warning preparedness meteorologist with Environment Canada.

"January is traditionally the coldest month in the Ottawa area, but here we are experiencing yet another January that hasn't quite reached or even come close to the long term average for the area," he said. 

There's been only a short stretch of colder temperatures this year, from Jan. 15 to Jan. 21, Coulson added. 

Last month was the sixth warmest January in Ottawa's recorded history, just after last year's January average of –5.9 C. The warmest January on record was back in 1990, Coulson said, when the average temperature hit –4.6 C.

The average January reading by Environment Canada at the Ottawa International Airport in the 1980s, 90s and 2000s was about –10 C, with daily highs around –6 C and lows around –14 C.

This January has seen highs and lows closer to –3 C and –10 C.

These warm stretches are happening more often.

Six of the last 10 Januarys were warmer than that three-decade average, topped in 2017 at –5.6 C.

Nine of Ottawa's last 12 months have been warmer than average as well. The last 365 days have been 1.1 C above average, according to data compiled by CBC's Climate Dashboard.

These milder temperatures can be attributed to El Niño, which can raise the global temperature and alter weather patterns across the planet. That includes eastern Ontario, where changing winds have kept some of coldest temperatures up North.

"That isn't really all that normal In the winter. We normally expect to get outbreaks of Arctic air," Coulson said.

Snowpack cut in half, canal shut

That run of colder temperatures in the middle of the month helped open a portion of the Rideau Canal Skateway, which then closed three days later because of warm, wet weather. 

On the eve of the annual Winterlude festival, the skateway remains closed.

Ottawa's snowpack was zero centimetres on New Year's Day. It peaked at 27 centimetres on Jan. 17 and has since melted down to about half that depth.

Climate researchers such as those involved in a 2023 Ontario report allow that there are some benefits to warmer weather for industries such as agriculture, fishing and recreation, but say the harm outweighs the good.

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As people continue to burn fossil fuels and pump greenhouse gases into the atmosphere, the planet continues to warm. 

As of 2010, Ottawa's average annual temperature was 6.7 C, 0.7 C warmer than the previous three-decade average. By 2100 it's projected to be 2 to 6 C warmer, depending whether and by how much humans cut emissions. 

There have been years of warnings about climate change making local winters warmer and wetter with more freeze-thaw cycles.