Warm weather delays vibrant fall colours across GTA

Recent warm weather is delaying fall colours in parts of Ontario and that means the leaves of many trees in the Toronto area are still pretty green.

Dawn Bazely, a biology professor at York University, said the leaves are turning yellow, orange and red more slowly this year than in previous years.

And that means the leaves may still be green for Halloween, which will be "very strange," she said. Fall colours, a natural spectacle, draw hundreds of tourists to Ontario every fall. 

• Fall colours could be 'drab' in southern Ontario

And the fall colours themselves may be less vibrant this year, she said. Temperature, sunlight and precipitation can all affect the intensity of leaf colour.

Toronto's wet summer and extremely warm start to fall have slowed the chemical process. 

"This is an exceptionally late, late season," she said.

"I feel very cheated, I must say, when I don't get spectacular fall colours because I must have a million photographs of trees in the fall. I just can't stop taking photographs of them."

Leaves appear green because of a pigment called chlorophyll. Different pigments of yellow, orange and red, are always present within leaves as well, albeit in different proportions for different species.  

As the days get cooler, chlorophyll production declines. As fewer green pigments are made, the other pigments start to show through, giving us the striking colours of autumn. Eventually, the leaves start falling from branches onto the ground.

"That process is happening when nights are cool and days are sunny. What is happening now is we are not getting those cool nights, so the leaves are still green," she said. 

"And because we got a lot of rain, it was a very wet summer, the trees are not drought stressed. Under the warmer conditions, they are doing just fine. They have enough water to make that green chlorophyll."

Bazely said determining when fall colours will peak requires taking a hard look at the long-range forecast, which doesn't anticipate consistently cooler nights until November.

If Ontario doesn't get sunny days and cold nights, the fall colours could be muted and leaves could shrivel up and fall without having changed colour.

In Rouge National Urban Park, a Fall Walks Festival has been drawing crowds since Tuesday, even though the colours have not reached their peak. The festival, which runs until Monday, features 29 walks in all.

"We are starting to see changes in leaf colour especially in the last couple of days," Omar McDadi, external relations manager for the Rouge Park, said Saturday.

"We're getting some fiery reds and bright yellows. It's starting to look and feel like fall. The park is one of the best places in the GTA to see fall colours."

According to Ontario Travel, the official marketing agency of Ontario that tracks the changing colours of the leaves across the province in a "Fall Colour Progression Report," the percentage of fall colours that have changed are about a week and a half to two weeks behind what they were this time last year.

According to that report, only 10 per cent to 20 per cent of the leaves have changed colour in the Toronto area. It says the predominant colours here are greens, with reds and yellows starting to show. 

Kevin Forget, travel promotions officer for Ontario Travel said the delay in fall colours is disappointing because Thanksgiving weekend is often prime time for foilage tours. He said it is too early to tell if the delay will have an impact on tourism in the province. 

Some trees have brown leaves

Ontario Travel is directing visitors to areas where many of the leaves have changed colour.

"People are still booking at the resorts, they are still getting out, but the disappointing part in some of the areas is that the fact that people have come to Ontario specifically to see the fall colours.," he said.

"We are also kind of seeing right now that there is a bit of a trend, and it may be because of the summer weather, that some of the trees that were really kind of the vibrant reds before are changing colour, but they are more like a browny colour right now," he said. "The vibrancy isn't there."

Forget said one exception to the delay is the Sault Ste. Marie area and Agawa Canyon, where 90 per cent of the leaves have changed colour. "That's at the peak right now," he said.

After the season is over, the agency will assess whether the delay resulted in fewer road trips in Ontario.