Paolo,
Firstly its not the weather, if you're giving the weather as the main reason to move then you need to re-examine yourself, I know I've been there and done that.
I emigrated to Australia (Perth) in 1995 from London, this was one of the best decisions I've ever made.
In 2000 I moved to the USA for reasons to complicated to go into here, we lived in San Diego, the San Fransisco bay area and lastly Houston.
The USA is a big and diverse country which I love (married my California girl
) but to live there successfully you need to be able to do the kind of work you want to do in the area you want to live, I couldn't find that so we moved back to Perth in 2005 and are once again happy as can be.
In general moving to the USA is hard, the INS is complex, slow and stupid to deal with and there's no real organized plan to take skilled migrants into the USA that I know of, so unless you find a job ahead of time or are going to marry a girl from the USA it is very hard.
Australia's system is much more straightforward and even if you do get a job offer beforehand I'd recommend going through the points system as it will mean much less issues in time.
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