Well, climate zones are just an indication and 10 years ago, I was in zone 8a :
−12.2 °C (10 °F) | −9.4 °C (15 °F) |
We would have at least a couple of nights with temps below 10°C.
But each year, the temperatures get a little higher, this winter we had one night at -5°C, and a few nights between 0°C and -3°C, not very many.
So now I'm actually more in USDA zone 9a :
−6.7 °C (20 °F) | −3.9 °C (25 °F) |
About 150 yards from where I live, a neighbour planted one of these many olive trees that are imported from Spain 5 years ago. I thought at least the top would drop its leaves, but no, it's in perfect shape. That would have been unthinkable 10 years ago, when we still had a few days of snow in December and in February.
I'll change the info in my profile - though climatology is not an exact science.
PS: from what I heard, or read from friends and maple lovers, not all species/cultivars react the same. Like us, they'll have to adapt themselves to new conditions.
Like not shaking hands, not kissing friends on the cheek, etc.