So the amount of water vapor in the air might be the same, but the air is capable of holding more than it was able to hold at the lower temperature. So the percent ratio of the two quantities goes down. I don't have Daniels and Alberty handy. Absolute humidity doesn't tell you much as far as plant cultivation is concerned. The weather reporters don't use it.
Relative humidity works just fine for our application.
Hi all, I live in a middle Europe, in elevation 400m. Even the S.purpurea x leucophylla is also alive. The D.arcturii were in a very good condition during the summer. I don't understand why. On natural sites of D.arcturi in New Zealand freeze too.