IYO is available for the Fall (September) and Winter (January) intakes. The terms for Fall intakes are September to December and January to April; for Winter intakes the terms are January to April and May to August. You need to take the two terms consecutively (you cannot take a break between term 1 and term 2).
Note that the Cities Regions Planning (CRP) program in EUC is only available for the Fall term.