According to Orillia amateur weather watcher David Brain, it has been one of the warmest Septembers on record in the region.
The warmest September on record in Orillia was in 2002 with an average temperature of 18.6 degrees Celsius. As September faded this year, the average temperature was at 17.8 degrees Celsius.
"One of the factors is what they call the North Atlantic oscillation," Brain explained. "What's happening is the Northern Atlantic is warmer than normal which is allowing warmer Pacific air to stream across Canada."
Brain's projections are showing that the typical crisp fall weather is coming. He says the week of Oct. 7 will bring temperatures that are closer to normal averages.
"We might even see some frost," he said. "There's a more progressive pattern and we are going to start seeing changes."
However, temperatures may rise above average again after the Thanksgiving weekend. As of right now, Brain says October is projected to also be warmer than normal this year.
"How much warmer is still unknown," he said. "The funny thing is it gets warmer and warmer each year, but we are still seeing snow in October and on Halloween."
The warmer-than-normal autumn season could result in more snow for the winter months, he warned.
"The warmer it stays longer, the better it is for snowfall," Brain said. "Once we get into late October and November, you'll get the colder air coming off of Georgian Bay for lake effect."
It takes a 13-degree Celsius difference between the water and air 5,000 feet up to make lake-effect snow, Brain explains.
Looking ahead to winter, Brain says projections are showing a milder than normal winter, which could also help create some heavy snowfalls.
"Last year we had above normal snowfall in November and then December was slightly below normal," he recalled. "The snow was gone before Christmas and the ice left Lake Simcoe in March before the huts needed to be off the lake on the 15th."
Brain wonders if we are in a progressively warmer weather pattern or if warmer winters are the future for Simcoe County.
"It's too hard to tell," he said. "There is a study on underwater volcanoes that could be heating up the ocean more than we think, creating warmer temperatures."
Typically, every year balances out with warmer and colder than normal temperatures. That is no longer the case, he explained.
"The last three or four years you aren't seeing that," Brain said. "There is a continual climb on the graph of temperatures above normal."
At one point in September, temperatures were three degrees warmer than usual.
"That's significant," Brain said. "We haven't seen a lot of the results of climate change here over the years, but it makes you wonder what is happening."
