The US is officially in a recession when the National Bureau of Economic Research says we are. Two quarters of shrinking GDP is often used as a heuristic but other factors like duration and intensity are included as well. Sometimes labor and unemployment data gets corrected months later, so it is sometimes the case that a recession is not official until it has already passed.
Basically, in the US, we are in a recession when the Business Cycle Dating Committee says so.
Basically, in the US, we are in a recession when the Business Cycle Dating Committee says so.
https://www.nber.org/research/business-cycle-dating