[Grammar] to ensure that comes/come November

[Oceanlike]

I don't know whether "come" or "comes" is correct. I think it's "comes" because of November ie. November comes. If this is wrong, what is the reason?

- They are working hard to ensure that comes November, they are ready for the launch.

Thank you.

 

[Rover_KE]

No — 'come' is a preposition in this context, so 'come November' means 'when November comes'.

 

[bubbha]

I would write it like this: "They are working hard to ensure that, come November, they are ready for the launch."