The Canadian event moved from its historical date in mid September to June because of low temperatures. 5°C wasn’t usual. I’d be surprised if Liberty would take the risk and I suspect Pirelli would probably get a bit jumpy. There are similar weather problems with Hockenheim around that early October date though.
I thought the Istanbul Park facilities were in a serious state of disrepair. It isn’t on the FIA list any more, the current owners probably wouldn’t be up to running such a large event at short notice either.