User blog comment:Omega natsu2/Fairy Tail Episode 206: Panic of Library, Review./@comment-4449950-20141101042510/@comment-7418318-20141101094255

3 mins = 4.5 hours. 2 mins = 3 hours. So as SilverShock said, the timing could work out even if the 1:90 difference is still in place.

But remember that in the previous ep we were told about the worlds blending into each other. That might cause the time dillution to be less severe and might also be the very reason for the unsusual weather. Two different flows of time crashing together sounds like a recipe for disaster to me.

About how Natsu managed to fall out of the Spirit World I also theorized around a but further down in the comment.

But I agree on the little trip to the Spirit World serving little purpose for the story, except to get Natsu out of the way so that Yukino and Lucy could fight Virgo on their own... but that could also have been accomplished by having Taurus or some other Spirit accompany Virgo to the library.

We already know that Natsu is compulsive and doesn't think things through before acting. We don't need to get that fact slapped into our faces in every single episode.