luck of the moment; chance; fortune of the times
A set phrase meaning that an outcome depends on luck or the circumstances of the moment, not on personal effort or ability. Often used when accepting an unpredictable result.
I think winning was just luck of the moment.
Whether you pass the exam or not is a matter of chance.
A compound of 時 (とき, 'time') + の (possessive particle) + 運 (うん, 'luck'). The phrase literally means 'the luck of the time' and has been used idiomatically to refer to chance or fortune dependent on circumstances.