ترجمة - برتغالية برازيلية-يونانيّ - Uma andorinha só não faz verão

Note: Φέρνει means "brings" because in Greek we wouldn't use "Makes".

There IS a saying in Greece with the same meaning. It is
"'Ενα χελιδόνι δεν φέρνει την άνοιξη"
"One swallow doesn't bring the spring"