Cold and dry would be just as good. It's the dryness that matters.

What really decided what texts survived and what didn't was monastic traditions in in the Dark Ages and Middle Ages [1]. At this time, a monk might spend their entire life transcribing a particularly long manuscript. The materials were also expensive. So monasteries were selective in what got retain and unsurprisingly it skewed heavily to texts of religious significance and then to texts of significance to, say, Roman and Greek tradition and history given that monasteries were European.

[1]: https://spokenpast.com/articles/medieval-monks-erased-preser...