How about asking for context if it's not clear? Any reasonable human assistant would ask if the context is not clear (enough).
"No, I meant the time in London, Ontario"
"Sure. The time in London, Ontario, is 3:23pm."
You start by doing a best guess, and actually listening for a correction. For other kinds of requests, you reply with a best guess and ask for confirmation or for clarifying questions.
Hard, yes. Not impossible.
“What time is it in London?”
... gives answer for London Ontario
“No, London England”
... gives answer for England
However there’s no memory to this; the same thing happens next time you ask.