Just how WARM is the upper deck?
 

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.

At roughly 35,000 feet (if that meets your definition of "aloft") the outside air air temperature is around -10 degrees celsius.

On the 747-400, you will, as on every other plane, be alternately too hot and then too cold in no particular order regardless of where you are seated. Enjoy the flight.

Airtemp decreases by 6 degrees Celsius for every 1000 m you go higher. So the outside temp will noway be near -10...

The aircirculation should be the same throughout the aircraft.

I get very uncomfortable in a hot, stuffy cabin, and have never noticed a problem during many flights on the upper deck.

I have worked the upper deck a few times, and have never noticed it to be any warmer or colder than the main deck. (I prefer a cooler cabin). The overhead airvents can help you stay cooler. If you think the temp. is way too warm, the flight attendants can adjust the cabin temp once the engines are running.

The only issues I've had have been on the ground. The 744's seem to have adequate A/C to keep the top deck cool on the ground in hot weather. The 742's apparently dont. I've boarded a 742 several times in hot weather and we've been asked to keep the shades down in the top deck until departure to keep it from roasting up there. It was a bit warm even that way.

Thanks to all!
 

Thanks very much for sharing your experiences with me; they all sound encouraging! Perhaps I'lll take the plunge after all and reserve a seat in the upper deck for the homebound flight.