6 month stay in canada

When you enter Canada you are given a certain period of stay. This is normally six months. That is calculated from the date on which you enter. Your question implies that you are wondering whether you can enter during the second half of a year and then stay until the end of June the following year. Generally speaking, you cannot do that under the normal rules for temporary visitors.

That all depends on immigration rules. Someone in your situation may also need to worry about tax rules. I don't know how Canada defines tax residence, but many countries do define it in terms thattake the calendar year into account. If that is your concern, you'll probably geta better answer on Expatriates.