Hello all: I have t dimension from Jan (1) to Dec (12). How can I compute average for winter season (Dec, Jan, Feb) using the function: ave(z,t=t1,t=t2)? Thanks in advance. FL -------------- next part -------------- An HTML attachment was scrubbed... URL: http://gradsusr.org/pipermail/gradsusr/attachments/20170914/f0570e9b/attachment.html