=TEXT(MONTH(DATE(A1,1,MATCH(B1,INDEX(WEEKNUM(DATE( A1,1,ROW(A1:A366)),2),),0))),"MMMM")

Which does *not* need to be array entered.

HTH
Steve D.


"KT" wrote in message
...
I have a worksheet with values for year and week number. I need to convert
these to the descriptive month name. Some weeks cross month ends, but
this
is okay, I just need a single value for each record. It could be the
month
of the first day of each week number. Using Excel 2003.

Thanks for your ideas.