When did Jesus die? The Gospels do not provide a single, unambiguous, answer.
This issue may be most easily addressed by breaking it down into more specific questions:
what hour of the day?
what day of the week?
what date in the month?
Hour of the Day
The Synoptics write that Jesus was near death by the ninth hour (Mk 15:34; Mt 27:46; Lk 23:44). In the Fourth Gospel, Jesus is before Pilate at the sixth hour (Jn 19:14). The most common way of counting the hours was to begin at 6 AM. This means that in the Synoptics, Jesus is near death at 3 PM, while in John he has yet to be crucified by noon.
Since there is no need to harmonize, I am satisfied to say simply that Jesus died sometime in the late afternoon.