Hot, dry summer could shorten the window to see fall foliage, forecasters say

The vibrant colours of Ontario's fall foliage could have a shorter display this year than expected after a hot and dry summer.

'The trees are not happy with this kind of stress,' Environment Canada climatologist says

Two women walk a dog on a trail on a cool fall day at High Park in Toronto in 2014. (Nathan Denette/The Canadian Press)

The vibrant colours of Ontario's fall foliage could have a shorter display this year than expected after a hot and dry summer.

Environment Canada senior climatologist David Phillips says the trees in Eastern Canada could soon show the effects of a hotter and drier summer than normal, and they may not hold on to their leaves for very long as fall colours arrive.

While the trees may not currently show signs of stress, they've had a difficult few months, with some parts of Ontario and Quebec getting 50 per cent or less rain than normal.

Evidence of the difficult summer could even show itself next year, when the foliage returns after the winter, Phillips said.

"We went through those five weeks during the dog days of summer when you normally reach your highest temperatures — we were seeing no rain at all. In many ways, that period when trees and crops are growing feverishly at the peak of their growing season, they were probably under greater stress," he said.

"The trees are not happy with this kind of stress. They may be crying uncle this fall."

People walk near Hog's Back Park as fall leaves change colours in Ottawa. (Justin Tang/Canadian Press)

Phillips said that a few rainy days over the past week may have helped, including significant rainfall in many parts of Ontario on Tuesday. But the long-term lack of moisture, combined with the sustained intensity of the summer's heat, have already taken a toll.

Phillips added that the Niagara region has been hit especially hard, seeing only about a third of the typical rainfall for the summer, even after taking precipitation from the past week into account.

Eastern Canada will likely see the leaves changing earlier this fall, Phillips said, and if storms with strong winds roll in, they could put a faster end to the season.

"My sense for people viewing the colour-change season is don't procrastinate. When (the leaves) do turn in mid-September, late September or early October, don't think that they'll be there the next week after that," he said.

There will likely be good weather for watching the autumn leaves, with forecasters predicting warmer temperatures than normal in September and October.

Phillips said it's too early to tell how much rainfall there might be in the coming months.

Gorgeous fall colours seen at Forest City National Golf course in London, Ontario, last year. (David Donnelly/CBC)