I live in UK currently and everyone says their salary per annum :-)

nobody I know (here in England) would say their salary is their weekly earnings. Salary is always per year

When I did a summer holiday job during my A-levels, people talked about hourly rates and got paid weekly; when I was at Aberystwyth at the end of my degree, I remember some local employment scheme that listed pay per week; I think the job contracts after I graduated and before I moved country were usually listing annual pay, but I can't remember. Now I'm in Berlin, discussion is mixed between monthly and annually.

yeah for temporary/part time work you'll often have hourly rates with weekly pay, but that wouldn't normally be called a salary

Sounds like it’s English thing, that monthly- and yearly-income shares the word ;)