Question about the weather

[アンジェル]

Is the weather in the game scripted or am I just that lucky to have often incredibly atmospheric encounters?

Just had an encounter which went like this:

I entered the area and it started to rain. The rain is red looking like blood (demons: yeah... looking like blood, right...) and it started pouring so much that the whole ground is covered. Then my encounter awaited me. Talking about how they waited for me and such. Thunder and lightning hit the ground here and there next to my party. Then the battle.

And by the end of the battle, the rain stopped. Clear skies ahead.

That was really cool, so I started to wonder. I have had multiple similar awesome weather atmospheric encounter and thought it is just random. Now I cannot help but wonder.