I like the specific mention of "dew" in the new translation of Eucharistic Prayer II, which is a clear translation of "Spiritus tui rore sanctifica", as opposed to the present lame duck translation "Let your Spirit come upon these gifts to make then Holy", where rore, dew,is omitted entirely.
"Like dew" is such a good image of the Holy Spirit. At Pentecost the Holy Spirit comes with the sound of roaring wind and tongues of fire but for the most part it comes "like dew". It is gentle, almost imperceptibly. Charismatics and Pentecostals give the impression of being taken by violence, almost being raped by the Holy Spirit, but that is not the sense conveyed by the Church's liturgy. In the New Testament itself St Paul identifies the Holy Spirit as the "Spirit of Holiness", the list of fruits of the Spirit are those things which make a Christian Christ-like growing like a seed, unperceived.
Passover was the barley harvest festival, Pentecost the wheat harvest festival; barley was chewy, impossible to grind finely, wheat, gentler more digestible.
In the Byzantine Rite green not red is the Pentecost colour. Green illustrating the Holy Spirit's fecundity, hence in the West green is used in "Ordinary Time", formerly "Time after Pentecost". It is during this time of the Holy Spirit, that like the dew the Holy Spirit was gently at work in the Church, sanctifying it. Red, I suspect was the Roman Church's Pentecost colour because its experience of the dew of the Holy Spirit was so often about shedding blood in martyrdom.
In various parts of Africa and South America, where rainfall is virtually unknown, the growth of anything is dependant on unseen dewfall.
How we perceive the Holy Spirit is important, is it the thunderstorm of "Majesty" with percussion, synthesizer, mics and arm waving, or gentle plainchant with its soaring notes? Is it young men and women stomping in their new found conversion or old men and women in the fortitude of faith quietly trusting in God's mercy? If it is the former then for 2000 years the Holy Spirit has been absent in the Catholic, if it is the latter then he has been present in great abundance.