adding months to date-but excluding months of summer

[tziviak2]

I have to add a certain amt of months to a date -but I need it to calculate it-excluding summer months(2)
ex. if startdate is 9/1/05-and I'm adding 9 months-the result should be 6/1/06
but if I'm starting in 4/1/05 and I'm adding 18 months-it should exclude the 2 summers inbetween and the result should be 2/1/07 and not 10/1/06.

thank you

 

[genomon]

Where are there only two months of summer? Which months do you need to exclude?

I have great faith in fools; self-confidence my friends call it.
-Poe

 

[tziviak2]

july and august-but I think I took care of the problem -I made a for loop and when it hit month of "7" I added 2 months to it.
have any more efficient way?