The month of October has given Ontario a long stretch of well above seasonal temperatures, at times with blasts of late summer-like heat that brought back humidity and thunderstorms -- typical aspects of the summertime.
As we fall deeper into the heart of the season, all good things must come to an end, and these 20-degree days will be harder to reach going forward. After a toasty Tuesday, which saw Toronto's Pearson airport hit 21.1°C, Wednesday may actually offer the last of them for 2021.
"October is a transitional month and is known to have some warm days, but the chance of 20°C daytime highs decreases as you go later in the month," says Matt Grinter, a meteorologist at The Weather Network. "But that still doesn't mean there isn't the chance in November, it just becomes a lot more rare."
Since record-keeping began in 1937, there have only been 25 days that have hit 20°C or above, which is only one per cent of total November days. Even more rare is cracking the 20-degree mark in December and that has only happened once in history. On Dec. 3, 1982, Pearson airport hit 20°C, making it the latest date for the region to be that warm.
With abundant sunshine in the forecast Wednesday, this will truly be a beautiful October day to enjoy. Daytime highs will be into the low 20s across a good portion of southern Ontario, and some areas in central and eastern sections may even hit the 20-degree mark.
Beyond Wednesday, an upper trough hanging over Central and Eastern Canada will bring an end to our gorgeous fall weather. The setup will allow for multiple systems to track in, with cloudy, showery and cooler conditions set to take shape late week and on the weekend.
"The pattern change will definitely be cooler, and since we have been so warm this month, the incoming cool down could feel down right frigid for some," says Grinter.
By Friday, a much colder pattern settles in, persisting through this weekend and early next week. Temperatures will be close to seasonal or even a few degrees colder than seasonal -- quite a contrast to what we have seen so far this fall. The weekend won't be a washout, however, as there will be some peeks of sunshine with passing showers.
We could even see some lake-effect flakes across the higher terrain, south of Georgian Bay.
After a cool start to the week, a couple days of warmer weather returns mid-week, ahead of the fall storm that is expected to track into northwestern Ontario.
Looking even further ahead, there will be a cooler start to November, as well, making it that much harder to reach 20°C as the seasonal daytime high for the first week of November drops to 9-10°C.