The ‘Super El Nino’ is upon us. What does that mean for Ontario’s fall colours?

Ontario could be in for a muted autumn foliage display this year due to the "Super El Nino" climate pattern, but experts emphasize that the stunning fall colours will still be on display. Dubbed the "Super El Nino," this climate phenomenon is disrupting global weather patterns, causing droughts in some areas and flooding in others.

Scientists predict a warmer-than-normal fall in Ontario, which may delay the vibrant colour progression, but still allow for an impressive display of orange, red, and yellow pigments in the leaves.

Biology professor Susan Dudley from McMaster University explains that cooler nights typically trigger the big change in colour, but the warmer El Nino weather might delay this process in some regions or result in a longer period of colour change. Although last fall's colours were duller due to limited rainfall and hotter-than-normal summer weather, the trees this summer have remained healthy and continued to produce foliage.

The yellow and orange pigments in leaves become visible as trees withdraw nutrients from them before shedding, with red and purple hues stemming from anthocyanins that protect plants from ultraviolet light. The brightest colours occur when trees receive bright daylight and cooler temperatures. However, El Nino's warmer days may result in slightly less vivid foliage this fall, as trees require less anthocyanins for protection.

Ontario's fall colours are renowned for their breathtaking beauty, thanks to the variety of woody plants, including maples, and the province's ample daylight during cold fall days. David Phillips, a climatologist with Environment and Climate Change Canada, notes that the combination of rainfall variation and warmer-than-normal temperatures has been ideal for the trees to remain healthy and produce vibrant foliage.

El Nino's warmer weather also offers fall enthusiasts the chance to view the stunning colours without freezing. According to Phillips, the right mix of temperatures and rainfall will allow trees to cooperate and display their beauty, making Ontario a prime location for enjoying the fall foliage. The colours will progress from north to central Ontario and the Greater Toronto Area, with Algonquin Provincial Park already showcasing the best sugar and red maple foliage at the canopy level.

While the normal window for fall foliage in Ontario is mid-September to late October, El Nino has pushed back the peak display by a few weeks this season.