when is a good time x when is it a good time

[beachboy]

When is a good time to go to London?
When is it a good time to go to London?
I've found both types of sentences after googling them. I came to the conclusion that both can be grammatically right. If so, which one is more common in everyday English?

 

[SoothingDave]

I find the first the most natural.

Unless it's something like:

February is a horrible time to go.
Well, when is it a good time...

 

[emsr2d2]

I find the first the most natural.

Unless it's something like:

February is a horrible time to go.
Well, when is it a good time...

And even then, "Well, when is a good time ...?" is a perfectly acceptable response.