Amber F. answered 07/10/19
6 Years of Classroom Teaching Experience
To understand the line you have quoted requires some Old Testament knowledge was well as a careful reading of the passage in context. I will explain what is going on here in order, starting from the preceding context.
First, in the paragraph just before the one which refers to the "dew of Hermon," Jude is thinking "what a wicked and worthless fellow he had been to give vent [. . .] to an animal passion for a woman [. . .] then to think of putting an end to himself; then to go recklessly and get drunk." In other words, he feels sorry for indulging in lust for a woman, contemplating suicide, and then getting drunk. If you read that whole paragraph, in his state of feeling sorry for his failings, he is wondering how he can "cleanse his way" (reflecting on the song that is being sung in church just then), and he feels like the music that is being sung applies so perfectly to his life that it feels like it was meant just for him.
In that mental state, Jude sees Sue and thinks she is "probably a frequenter of this place [the church], and steeped body and soul in church sentiment." In contrast to the other woman, to whom he had only a physical attraction and who was not able to offer him any meaningful intellectual or spiritual companionship, he believes that Sue, because she goes to church regularly, has a lot of thoughts and sentiments in common with him and is a pious and pure-hearted person who can give him the sort of edifying intellectual and spiritual companionship he desires.
It is this thought about Sue--that she can offer this kind of intellectual and spiritual companionship--that Jude says is like the "dew of Hermon." To understand what "dew of Hermon" means, you can take a look at Psalm 133 here: https://www.biblegateway.com/passage/?search=Psalm+133:2-3&version=NIV
Basically, if you look at how the phrase is used in the psalm, it means "refreshing." Jude's imagining that Sue can give him uplifting intellectual and spiritual companionship that will be a positive influence in his life is a refreshing thought.
For the next line you quoted, you need to know what the Biblical associations are with Galilee and Cyprus.
Galilee is simply the place that Jesus came from.
For Cyprus, you can take a look at the places where Cyprus is mentioned in the Old Testament here:
https://www.biblegateway.com/quicksearch/?quicksearch=cyprus&qs_version=NIV
The main things to know are that it is a wealthy and prosperous city involved in trade, similar to Tyre and Tarshish, and that it is a gentile (pagan) city, not a Jewish one.
Therefore, the quote which says the wind blew as distinctly from Cyprus as from Galilee means that Jude's thoughts are at least as much from Cyprus (wordliness, paganism; here mostly meaning "worldly desires" but also being NOT associated with Judeo-Christian religion) as they are from Galilee (Christian religion).
So, although Jude thinks that he is being pious and getting on the right track by feeling attracted to a woman he thinks of as being a pure, spiritual, devout soul, actually, his feelings are just as much influenced by worldly desires as they are by religion (if not more so).