To the Samaritan woman:
"the hour is coming, and is now here, when the true worshipers will worship the Father in spirit and truth, for the Father is seeking such people to worship him" (4:23)
To the Jews:
"an hour is coming, and is now here, when the dead will hear the voice of the Son of God, and those who hear will live" (4:23)
To the Disciples:
"the hour is coming, indeed it has come, when you will be scattered, each to his own home, and will leave me alone." (16:32)
So "the hour" in John seems to be Christ's death and resurrection and the breaking in of that Old Creation death and New Creation life into our present.