[identity profile] drasecretcampus.livejournal.com 2012-08-25 09:06 pm (UTC)(link)
A similar issue comes on, say, a Tuesday, when you say "Next Thursday", which could be confused with "This Thursday".

On the other hand, "Thursday after next" might actually be a week after this Thursday.

[identity profile] sam-t.livejournal.com 2012-08-28 09:57 am (UTC)(link)
In that case I think I'd avoid saying 'Next Thursday' at all, and instead use either 'This Thursday' (the day after tomorrow) or 'Thursday Week' (seven days after that).

I think 'last May' is ambiguous from June to about now-ish. 'This May' will mean May 2012 until January 2013, unless clarified with '-coming' or '-past'.