Daily heat records smashed across B.C. as subtropical winds whip through province

The calendar may read Dec. 1, but in parts of the B.C. Okanagan it felt more like mid-June suntanning weather. 

Just after 1 p.m., the temperature in Penticton reached a new daily high of 22.5 C.

That's more than 10 C warmer than the previous heat record in the city for Dec. 1 of 11.2 C set in 2012, and vastly hotter than the historical daily average of 3.4 C.

Even more, Penticton's 22.5 C ties it for the all-time Canadian heat record for the month of December set in Hamilton, Ont., on Dec. 3, 1982.

CBC meteorologist Johanna Wagstaffe calls the situation exceptional and explains that the heat was brought by the atmospheric river systems that have soaked southwest B.C. in recent days. 

"Winds are very strong from the south today and that's basically transporting the warm [subtropical] air. It's the same reason why the tops of our mountains are melting right now," she said Wednesday.

"We do expect these warm-ups when we get these river events, but this is very warm."

Down the road from Penticton, thermometers in Summerland climbed to 20.7 C, smashing the daily heat record of 11.3 C recorded nine years ago.

Records also fell in surrounding cities, including Kelowna: 17.4 C versus 8.7 C in 2006; Vernon: 17.5 C versus 11.2 C in 2012; and, Osoyoos: 18.1 C versus 12.3 C in 2012.

In total, Environment Canada said Dec. 1 high temperature records were set in 20 B.C. towns or cities.

The mind-boggling temperatures are in line with the extreme weather B.C has seen throughout 2021.

On June 29, Canada's highest ever temperature of 49.6 C was recorded in Lytton during a provincewide heat dome. The next day, a wildfire burned the entire town to the ground.

Large swaths of B.C endured historic droughts and wildfires throughout the summer, only to be hit by successive atmospheric rivers in November that brought record-setting rains and triggered catastrophic mudslides and floods.

Environment Canada meteorologist Armel Castellan said the extreme weather is consistent with climate change projections.

"It's not going to be this extreme all the time. We will see lulls," he said. "But the frequency, the amplitude of these events and their longevity will continue to increase in the coming years and decades." 

Temperatures throughout the Okanagan are expected to return to "normal" by the weekend. The forecast for Penticton on Sunday calls for snow flurries and a high of -1 C.