Excerpt from blogto.com:
The Top 10 Places to see Fall Foliage in Toronto:
The Don Valley
There's no better place to take in fall colours in the city than the Don Valley ravine system, which extends further north than most people realize. Crothers Woods and the Brick Works are top spots, but so too are Taylor Creek, Sunnybrook Park, Edwards Gardens, and the East Don Parkland. Peak colour usually takes place just after Thanksgiving.
Glen Stewart Ravine
One of the best places to take a walk in the entire city, Glen Stewart ravine explodes with colour in mid October. The walking trail that cuts through the heart of the park places you directly under the tree canopy so that that you feel as if you're at the centre of an explosion.
Moore Park Ravine
Starting at Mount Pleasant Cemetery in the north and heading southeast down to the Don Valley Brick Works, Moore Park Ravine follows the almost vanished Mud Creek. It's not one of Toronto deepest ravines, but the hard-packed trail is perfect for a leisurely walk or bike ride.
Nestled in the Rosedale Ravine, the Necropolis Cemetery is seems like a world away from the rest of the city, even as you can occasionally catch a glimpse of the apartment towers of St. James Town. Harolding isn't for everyone, but there's no better time or place to contemplate one's finitude than a cemetery in fall.
You can hike the many trails that meander around the ravine walls, but this is also an area that's good to drive around in a car. Head to Old Finch Avenue and drive around the Toronto zoo. The scenery is so rural you won't believe you're still in Toronto.
The Scarborough Bluffs are beautiful no matter what time of the year it is, but something extra special happens when the trees turn colour here. The combination of bright leaves and an azure Lake Ontario looks like a Group of Seven painting. Head to the beach or hike the trails that line the top of the bluffs.
The Humber River has a slew of parks that line its banks from Lake Ontario all the way to Steeles Avenue (and beyond). Favourites include, Lambton Park, Humber Marshes Park, Etienne Brule Park, Raymore, and Summerlea Park. Weekend activity: start at the water and travel the whole valley in the course of a day.
Little needs to be said in endorsement of High Park as a destination for fall foliage. The best part is that there's so much to do here beyond hiking the trails that you can easily spend the day surrounded by fall's splendour. Hit up the zoo, lose your kids at the Jamie Bell Adventure Playground, feed some ducks, or do a crit around the roads..
The best part about a fall trip to the Islands is that it's way less busy than in the summer months, which allows for more leisurely exploration of the astonishing number of tree species the area has on offer. If you can manage it, take the ferry over on a weekday. It's wonderfully tranquil and the bustle of the city seems so far away.
Leslie Street Spit
Water, sky, and leaves. The Leslie Street spit might not feature as many trees as the ravines on this list, but it's still a gorgeous spot to witness the onset of fall. It's the perfect place for a mid-October bike ride. Head to the lighthouse at the end, and wonder how something that was once so ugly has transformed into one of the most pretty places in the city.