I'd be curious to know what countries don't start the year January 1st and where the origin of their chosen day comes from.

I know China's new year is different by a ~3 weeks?

Also, I only know a little USA and Japanese culture but it's interesting various calendar related things like where I grew up, SoCal, elementary, middle, and high school school started 2nd week in September. College also started around the same time. In Japan it starts first week of April and so do new jobs for college grads (Japan generally makes a distinction between no-experience college grads and experienced employees and job listing will often say which one the job is for)