Hi im moving to calgary in may do i need some sort of health care cover before i get there or do I take it out after landing the health care varies depending on the province

thx

It is not mandatory to have any coverage for initial 3 month. But hey, it's insurance, you never know!
You can get it within few days of landing. I don't remember exactly, but for me, it took ~2 days.
Besides, it depends on your address. If you are sure of where you are going to land and stay, you can get the coverage in advance.

Next, if you are already having a job offer, then remember that companies do offer health coverage. BUT this coverage is "on top of" provential or private health coverage. So having private coverage during initial wait time is recomended.