my son was diagnosed with bronchial spasms when he was 18 months. This was after about 9 months of continuous doctors visits and specialists and 5 different rounds of antibiotics. We started giving him a nebulizer treatment twice a day. This was difficult to do because you have to keep them still. Anyways, the treatments helped alot and now two years later he's doing alot better and we rarely have to use the nebulizer anymore. Just be wary of how many steroids they prescribe for him---- they can make him kind of hyper. I don't think the heat was ever a factor for us--- I'm not sure I would cancel a trip. They may also give you a traveling inhaler. I'm sure he'll grow out of it, although I know it can be EXTREMELY Frustrating! Also, my son's bronchial spasms flamed up whenever he got a cold so I started giving him probiotics in the morning to strengthen his immune system and that has helped ALOT. Good Luck!