It's real easy to google That......

But looks like yours is 6a

That is the map I was using too; or you could look at this link:

ontario zones

- it will give you also important dates & more info.

Just discovered I'm in 6b. I always thought I was in 5a.

Elizabeth, are you also in TO?

No, I'm further south, at the border.

Thanks MrBlubs, rina_ & elizabeth_101

On a Canadian Govt. website a chart says TO is 7a, but in a colour coded map it is more like 6a or even 5b. In the Ontario map it puts TO at 6b.

The whole thing gets complicated because it seems that every decade or so 'they' update the numbers, maybe for climate change, & come up with a new number.

Out of all that, I think that 6a is a reasonable compromise. I go with MrBlubs.

Canadian hardiness zones have been same for a long time (maybe 30yrs?). They are 'calculated' differently than USA.

Plant hardiness zones in Canada

I use the zone as a guide; it is very difficult to use all local factors in such a large area. I think using average frost-free period may be better?
I used 6a & 6b as a good guide for TO...but grew some plants that were supposed to be hardy to z7a. (Above map is showing TO as 6a if I am interpreting the color coding correctly? Type in address, then click legend)