I live in Waterloo, Ontario. I have a climbing rose that is a prolific grower and bloomer ( I don’t know the exact variety). It has southern exposure against a brick wall. The soil is pretty good – I think. It has been amended and doesn’t seem overly heavy like clay – if anything maybe closer to a sandy soil. I just noticed the leaves on some of the canes are yellow and spotted. When I handled them some fell off easily. There are a lot of buds forming.
It looks like your climbing rose is suffering from rose black spot, a “classic” rose disease caused by the fungus Diplocarpon rosae, which infects the leaves and greatly reduces plant vigour. Please see this previous answer black spot on rose bush for an overview of this fungal disease and how to mitigate the damage. We wish you the best of luck in controlling the black spot and an abundance of blooms on your climbing rose.