I'm just interested in knowing. Personally, my panic disorder usually perks up every spring - I think its a combination of the pollen (I get sinus headaches, phlegm in my throat sometimes, overall gross feeling) and the humidity (very humid in Georgia in Spring and Summer) - those combined make me feel like crap - I can't breathe as well, feel like I can't take a deep breath, and that starts the panic - a -comin. Luckily I've managed to learn how to control them pretty well over the years.
In fall and winter I'm usually fine and have very few attacks - weird huh.