There are two situations. There could be a recession or an extraordinary circumstance, in fact. In the case of a recession, the proposed act indicates that the recession ends when Statistics Canada reports the second quarter of economic growth. In the case of an extraordinary circumstance, this ends at the time the public accounts are tabled, which shows the impact of that extraordinary circumstance, which needs to be greater than $3 billion.
On May 26th, 2015. See this statement in context.