Don’t be all masculine and just presume its hormones or ‘time of the month’. All that will do is annoy her even more and you will receive the silent treatment for hours maybe even days, don’t risk it! It isn’t worth the stress on both you and her and the arguments that will follow won’t help anyone. Don’t be so insensitive and blame her tears on being a girl, if she’s crying she wants you to be kind, not the sarcastic comedian you try to be. Girls are tougher than you think, we don’t cry for just any reason, so nine times out of ten there will be something going on.