Like Tongues of Fire
The Holy Spirit appeared as tongues of fire over the heads of the believers on the day of Pentecost or Shavuot.
It seemed as if Tongues of fire came and rested on the early disciples.
Time frame, the 7th Sunday or 50 days or 7 weeks after Passover.
Also the 7th Sunday after the resurrection of Jesus.
Called Pentecost, Feast of Weeks or Shavuot also called Whitsunday.
One possible date is Sunday 30th May AD32, which is early summer in Israel.
Another possible date is Sunday 24th May AD33, which is early summer in Israel.
Background Reading:
Acts 2:1–13
The Holy Spirit Comes at Pentecost
When the day of Pentecost came, they were all together in one place. 2 Suddenly a sound like the blowing of a violent wind came from heaven and filled the whole house where they were sitting. 3 They saw what seemed to be tongues of fire that separated and came to rest on each of them. 4 All of them were filled with the Holy Spirit and began to speak in other tongues as the Spirit enabled them. 5 Now there were staying in Jerusalem God–fearing Jews from every nation under heaven. 6 When they heard this sound, a crowd came together in bewilderment, because each one heard them speaking in his own language. 7 Utterly amazed, they asked: "Are not all these men who are speaking Galileans? 8 Then how is it that each of us hears them in his own native language? 9 Parthians, Medes and Elamites; residents of Mesopotamia, Judea and Cappadocia, Pontus and Asia, 10 Phrygia and Pamphylia, Egypt and the parts of Libya near Cyrene; visitors from Rome 11 (both Jews and converts to Judaism); Cretans and Arabs–we hear them declaring the wonders of God in our own tongues!" 12 Amazed and perplexed, they asked one another, "What does this mean?" 13 Some, however, made fun of them and said, "They have had too much wine."
More Information:
The Holy Spirit Came at Pentecost
Remember God and the burning bush - Exodus 3:1-4:17
Also read Acts 18 and Acts 19.