(1) the actual criterion is “NBER names it a recession, which usually happens significantly retrospectively, and start and end dates are often adjusted after initial determination.”

(2) the casual rule of thumb criteria, which is more objective at the starting end (“a period starting with two consecutive quarters of negative economic growth and ending...sometime later”) can also only be applied significantly retrospectively with regard to the starting point.

So, yes, under either standard, whether or not we are currently in a recession is generally an assessment made on the basis of trying to predict the future.