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A record-late fall frost stretched Thunder Bay's above-zero weather to 140 days

The frost-free period finally ended on Sunday
Thunder Bay's official frost-free period ended on Sunday when the temperature fell just below 0 C. at the airport.

THUNDER BAY — Thunder Bay-area gardeners have just experienced the city's longest-ever stretch of above-freezing temperatures.

According to local climatologist Graham Saunders, the city's new frost-free record is 140 days, beating the previous record (set in 2016) by one day.

A new record – Oct. 17 – has also been set for the latest first frost since record-keeping began at Thunder Bay Airport in 1941.

When the temperature dipped just below 0 C early Sunday morning, it was nine days later than ever before.

Saunders noted that this is only the third time that the first frost of the season has occurred as late as October.

"It illustrates that, overall, the temperatures in middle Canada are rising. This is not an El Nino year, so you can't blame it on anything else."

Historically, he said, frost can happen at Thunder Bay anytime after late August.

Saunders said there will continue to be a lot of fluctuation in temperatures from year to year, but there's an established trend toward a longer growing season in this area.

"I do a lot of gardening. This year we planted a second crop of yellow beans and green beans, and we are still harvesting a few of our pole beans. That's unheard of. Beans are fairly sensitive to frost."

He cautioned that gardeners shouldn't plan on this happening on a regular basis just yet.

"This is a bit of a fluke. It's consistent with climate change and warming, but it won't be an easy ride. It won't be an extra week every year."

NOTE:  This story has been updated to note that the previous record was set n 2016

Gary Rinne

About the Author: Gary Rinne

Born and raised in Thunder Bay, Gary started part-time at Tbnewswatch in 2016 after retiring from the CBC
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