I am still thinking about the 9th century. Here is an article that give the rabbinic background on the science of rain for the piyyutim for Shmini Atzeret.
Aleph: Historical Studies in Science and Judaism Volume 9, Number 1, 2009
Clouds, Rain, and the Upper Waters: From Bereshit Rabbah to the Piyyuṭim of Eleazar be-rabbi Qillir
In two Qillirian piyyuṭim for Shemini Atzeret—one seder yeṣirah and one rahiṭ—we observe the glimmer of an attempt to explain the origin of rain in a rational scientific manner. In this regard they are unique among pre-classical and classical sidrei yeṣirah (and rahiṭim) for rain, which treat the role of water and precipitation
We may observe first of all that although the rabbinic account makes use of the basic assumptions of its biblical counterpart—the existence of two cosmic reservoirs (Ber. Rab. 4:3–5) and the importance of clouds in distributing water (Ber. Rab. 13:10–11)—it is more naturalistic, in that it does not envision God as being actively involved in each and every act of rainmaking, but rather as having set up a process that continues to function autonomously, independent of His direct intervention. The rabbinic account also shows a greater interest in the structure and disposition of the heavenly reservoir: it is suspended by the Divine logos  (Ber. Rab. 4:3, 4), like a heated pool covered by a dome (Ber. Rab. 4:5), etc.
The most important aspect of the rabbinic view, that on which all the other speculations are predicated, is that the process that causes precipitation is unidirectional The upper waters are the source of the rain; but no matter how much it rains, the total amount of water in the heavenly reservoir is never diminished. This assertion is backed up by the analogy of the sweating man who, according to the sage, does not lose any weight (Ber. Rab. 4:4).The rabbinic view of precipitation as a one-way process with its source in a cosmic reservoir goes hand in hand with the absence of any notion of evaporation (and condensation)… The absence of a concept of evaporation, together with a notion of clouds as hollow vessels designed to transport water droplets
From this analysis, it is apparent that our piyyuṭim weave a narrative out of several of the midrashim cited above. In doing so, they combine views that are logically incompatible, so that whereas their narrative may be (in some measure) comprehensive, it is not internally consistent: The contribution made by the piyyuṭ literature with regard to the question of internal coherence is to underscore the incompatibility of the various midrashic accounts by inserting them in a narrative framework, which is something that piyyuṭ only rarely does.