Is it possible to close my account for a couple of months, then activate it again?

No, that is not possible.

If you close the account, Yahoo delete all the information, and it may not be recoverable when you decide you want to use the account again.

As long as you sign in at least once in 12 months the account remains open, so it should be okay for a couple of months of inactivity

It would be of no benefit to delete the account and reactivate it a few months later...From what I can see on Yahoo's help center your deleted account will still receive emails for awhile. As the other answer has stated just do not use it for a short time, but do not exceed 90 days as your account info might disappear.

You can always use a notification so that senders will know whatever info you put in it.

Hover your pointer over the GEAR (upper right)...click on

MAIL OPTIONS(Older format) or SETTINGS (Newest format)

...then click on VACATION RESPONSE...Fill in the necessary

info ...click on SAVE when done.

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To remove the vacation/out of office setup....

To remove.....Remove the check mark to the left of "Enable during these dates (inclusive)" click SAVE

Why would you want to do that? If you don't want it then delete it. If you do want it then just ignore it until you want it back