"Troo" wrote:
I have a list of data, the top row being months and the
bottom row being average temperatures. I need a function
that will find the highest average temperature, and then
return the month at the top of the list.

=INDEX(A2:Z2,1,MATCH(MAX(A100:Z100),A100:Z100,0))

where A2:Z2 represents "top row" and A100:Z100 represents "bottom row".
Change the ranges appropriately.