That won't give the correct result in all circumstances, e.g. on 30th and
31st May it'll return "March".
7th January 1900.

If you want to feed TEXT with a date 3 months ago, try
=TEXT(DATE(YEAR(TODAY()),MONTH(TODAY())-3,DAY(TODAY())),"mmmm")
[but remember the usual questions, such as what date do you regard as
being
3 months before 31st May?]

I'm not sure why my formula works when David's doesn't (for the dates you
mentioned), but I figured the actual date is immaterial for getting the
month, so I prefilled the year and day in and got this...

=TEXT(DATE(2000,MONTH(A1)-3,1),"mmmm")

which returns February for the dates you mentioned (the date being in A1 for
my example formula). So now the question is.... why does it work when
David's doesn't?

Rick