Thanks to all of you for your many informative responses to my previous question about deplaning from the upper deck. My other question about the upper deck concerns the air conditioning quality up there.

My outbound flight will be NW #17 from JFK all the way through to Hong Kong in mid-May; the return on NW #18 will be in mid-June. Could you share your experiences and recollections with me about just how WARM that upper deck of the B747-400 becomes once aloft in warm/hot weather? I have a touch of asthma, and would like a cooler rather than warmer sitting situation. Once again, thanks cordially.