Are signs enough?
On the Day of Pentecost there were signs, it is a day designed for miraculous signs.
What was the rushing wind?
What happened on the Day of Pentacost? What was going on!

Acts 2:1-4

The Coming of the Holy Spirit

2 When the day of Pentecost arrived, they were all together in one place. ² And suddenly there came from heaven a sound like a mighty rushing wind, and it filled the entire house where they were sitting. ³ And divided tongues as of fire appeared to them and rested^[a] on each one of them. ⁴ And they were all filled with the Holy Spirit and began to speak in other tongues as the Spirit gave them utterance.