Confused by this question, I find it difficult to ask a question about a number of occasions (about a single occasion, in particular) when there is a specific answer expected.
It's my first time in Ukraine.
I don't want to ask
Is this your first time in Ukraine?
Is this your first visit to Ukraine?
Have you ever been to Ukraine [before]?
because it can be answered shortly with a yes-no answer. I am looking for an idiomatic question structure starting with "what/which time/occasion", if there is any.
My abortive attempts like
What/Which time is it for you in Ukraine?
What/Which occasion is it for you in Ukraine?
sound awful and look completely incorrect.
The last time we went to Paris, it rained every day.
Suppose I know that they've been to Paris several times and that one of their trips was spoiled by [the ?] rain. I want to know exactly on which occasion it happened. How would I ask it?
My suggestion
On which occasion did it rain every day?
is just hilarious.
I am completely lost.
Best Answer
Answering this question, and this one, it did occur to me that there is a gap in English id you want to express a particular occasion when something happened in the form of a question. However, in real life, you would be able to work around it based on what you already knew.
For your Ukraine question, I would say:
If you want to deal with events which happened on an unspecified occasion during one of the trips, things get a bit trickier. But actually, your 'hilarious' suggestion is perfectly good. It sounds a bit formal, but grammatically it is fine. Here are some alternatives.