THUNDER BAY — This may not be the best year to take a dip in Lake Superior on a hot summer day – at least not yet.
The lake is taking longer than usual to warm up.
"It's been a remarkable year," says local climatologist Graham Saunders.
At the beginning of 2022, Lake Superior's average surface temperature was the warmest on record.
But the warmup that's supposed to come with spring began in June rather than May.
The result is that the current water temperature is the coldest for this time of year since 1997.
According to data from the U.S. National Oceanic and Atmospheric Administration, Lake Superior's average surface temperature on Tuesday was only 8.5 C.
In sharp contrast, at the same time last year it was 17.3 C.
"It's profoundly different now from last year, when we were four or five degrees warmer than normal," Saunders said. "We're the other way around, four or five degrees colder than average."
Saunders noted that when the wind is coming off the lake, this can also make for cooler days for shoreline residents.
He said it's not easy to explain what's happened this year, but he attributes it in part to the influence of La Niña, a periodic weather phenomenon that sees cooler than normal sea-surface temperatures in the central and eastern tropical Pacific ocean impacting global weather patterns.
From January to May, there were five straight months of colder than normal weather, which slowed the warming of the water this spring.
Saunders believes particularly windy conditions this year may also be a factor, as this has led to cold water from deeper in the lake mixing more with water at the surface.
He expects to see a significant warming of surface water over the coming weeks, even though the sheer volume of water in Lake Superior means that it takes a long time to respond to both warmth and cold.
Along the shoreline east of Thunder Bay, people were still swimming last October, "and it was relatively comfortable....a lot warmer than it is right now," Saunders remarked.
Until warming speeds up this month, the water temperature should still be at least somewhat more tolerable in specific areas.
"I think everybody knows that in the bays and shallow areas, the water will warm up a lot more than it does in the middle of the lake," Saunders said.
The temperature at Little Pigeon Bay, just south of the city, was 14 C on Monday.
