malkavian, if you are unfit for the exercise you are trying to do, then yes, you are going to be short of breath.
I know cold weather can trigger asthma in many people; I haven't heard the same for humid weather. What makes humid days challenging for exercise is that our bodies cannot cool as effectively so we are not going to feel as "fit" as we do on days where sweat works to cool the blood.
If you'd like to play soccer without getting short of breath, I suggest a basic fitness program to improve your cardiovascular fitness, like couch-to-5K.
49 yrs old, IBD diagnosis in spring '01. Proctitis, gastritis, ileitis.
Pentasa (3g/day)Colazal (9 pills/day), Sulfazine (1.5 g/day), Prevacid, folic acid, vit. D (2K iu), flax seed oil (2 tsp/day), mesalamine enema as needed. Gluten free as of 5/30/11.