Louisiana has hot (or hot + humid) summers and mild winters. It's not hot all year.
The southern half of Lousiana is culturally Catholic (not everyone is Catholic) and tolerant. Northern Louisiana is culturally Protestant (not everyone is Potestant) and less tolerant.
Much of the state is rural or semi-rural and there are no really big cities (the New Orleans metro area is about 1,250,000 and Baton Rouge is about 750,000). The total population of the state is about 4,500,000..
Louisiana welcomes visitors/strnagers. Another answer is correct and people will be intrigued by your accent, though may not be able to tell if you are from Australia, Britain, or New Zealand (also depends on how streretypical is your accent).
Few people you meet will know much about Australia beyond kangaroos, Koala bears, "Waltzing Matilda", or what they got watching the "Crocdile Dundee" films and "Crocodile Hunter" TV programs. Yes, that means you might be asked about crocodiles, kangaroos, and Koala bears. Do realize almost everything you know about the USA (and Louisiana) comes from the cinema and TV.
Almost no one you meet will know anything about Australian politics, or sports.
Sports are big - mainly baseball, basketball, and American football. Especailly LSU (university) football and New Orleans Saints (professional) football.
Church/religion is relatively more important than in the northeast US or on the west coast. You won't have any problems if you aren't religious or don't go to church.
Firearms ownership and sports like hunting & fishing are more common than in the NE or on the west coast. You won't have any problems if you don't own a firearm and don't hunt or fish.
You should visit and see for yourself.
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Unless you are independently wealthy, obtain a fiancé/fiancée visa, or have family already in the USA who will act as sponsors you will need a job to move to the USA. You need a sponsor (employer) for a work visa - you can't apply for one on your own.
http://travel.state.gov/visa/visa_1750.html Australians do have an advantage and can get an E-3 Work Visa (the "immigration support" website is a commercial site):
http://en.wikipedia.org/wiki/E-3_visahttp://www.usimmigrationsupport.org/visa_e3.htmlhttp://www.abc.net.au/pm/content/2005/s1366493.htm Check with US companies in Australia and Australian companies with offices in the USA. For example, Hilton and Marriott hire international staff as interns.
Australians and New Zealanders also qualify for:
http://newzealand.usembassy.gov/swt_faq.html Australian citizens can visit the USA for up to 90 days as a tourist, so you could travel for interviews & tests if necessary:
https://esta.cbp.dhs.gov/
http://travel.state.gov/visa/temp/without/without_1990.html Search "international exchange programs USA" and there should be many links to programs that offer temporary and seasonal work in the US. Examples are:
www.ccusa.com
http://www.bunac.org/australia/ Do carefully check any programs you might be interested in as not all of them are a good deal.
Another option is to go to school in the USA. Australian citizens can more easily get a US student visa and you MAY be able to work on-campus. Having a USA university diploma or certificate will make applying for jobs easier, and going to school in the US will help you decide if you really want to move here:
www.collegesintheusa.com
If you decide to go to university in the USA the first step is to identify several schools you might want to attend and make contact with their offices of international students
For example:
http://global.tulane.edu/oiss/ www.oiss.uno.edu
Good luck!