I'm probably not much help, since I've only lived in the U.S. Midwest all my life. But I can tell you that my fibro symptoms definitely get worse when the temp begins to drop, usually in September or October.
I also have a non-specific neuro condition, so I really shouldn't blame all my symptoms on fibro, but right now it's 27 degrees and I just got done shopping at Wal-Mart...and my feet feel like I've run a long marathon! They get very stiff and uncooperative.
Cold air is very nasty for my fibro symptoms; heat usually helps me.
We're all different--some people have success with using cold compresses, etc., but I definitely find heat to be a plus, unless it's really nasty heat, such as Andre mentioned. July and August here can be very overwhelming, with high temps plus high humidity.
Yes, storms can make a huge difference. Our poor fibro bodies don't seem to adjust to weather changes well.
Hope you find the right place to live---for you! Best wishes.