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
Michael Rand
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.
The Book of Doctrines and Opinions: 
As an afterthought, I realize that the Zohar uses this imagery for the initial watering from above from Eden, which is then maintained by waters of below. Since most academics note the sexual basis of the image, the meteorological ones do not seem to have been noted.
As someone who is writing on biblical, midrashic and zoharic myths on rain, I was caught by surprise by this article. Unfortunatley my surprise quickly turned to disappointment. Which is not to say this article is lacking merit, only that, as he himself writes in n. 42, “While the theme of the hieros gamos (“sacred marriage”) is related to the question of the precipitation process, the mythopoetic aspects thereof are not directly relevant to the way in which this question is posed here.” The way he poses the question therefore slices the material into two domains, the pseudo-scientific material, and more mythopoetic material. While there is some validity to this assertion it bequeaths him to explicate both how these discourses differ and the reasons why they are often intermingled in a single text.
More generally I find his approach to be overly formalistic. And J. Rubenstein (“From Mythic Motifs to Sustained Myth; The Revision of Rabbinic Traditions in Medieval Midrashim”, The Harvard Theological Review, vol. 89, No. 2 (Apr., 1996), pp. 131-159) has already argued for the same thesis regarding other 7th-8th century material, that they have no original material, but stylistically innovate by weaving isolated mythologumena into an extended narrative. And Rubenstein even uses these same rain midrashim to make his point!
I sense that my main difference here stems from our assumptions about the function of cosmographic rhetoric specifically in regards to rain. Rand claims that these are ultimately of theological importance, they seek to establish God’s awesomeness. I would situate this material within a more political context. The biblical texts on rain, irrigation and aquatonics seek to differentiate between meretricious lands that are abundantly watered from below (Egypt, Sedom, and Eden – see Gen. 13:10 and Duet. 11:9-11) and Israel, which is sporadically watered from above. Hence there is an ethics of dependency that drives the ecological discourse. Furthermore, its hard for me to imagine that the purpose of mythpoesis in regard to rain is ever descriptive and not productive. (Biblical) mythmaking thus shifts between a scientific and a technological function, at times explaining the oddity of nature, and at times providing unique techniques to control nature. This productive capacity is perhaps nowhere better exemplified than in myths surrounding rain; for the enigma of rain is not only how to understand its workings but more importantly how to ensure its arrival.
Do you want this placed into the post as an update?
What are the implications/reasons of/for that?
People will read it who show up from a web search will read it as part of the text. And placing it in the text means it is entered into search engines as a part of the text. If not, then I leave it as is.
As an aside, you seem to take an interest in the 6th through 9th century.
Are these non-systematic pre-philosophical & pre-Kabbalistic raw materials to fashion a post-Modern post-academic Judaism that moves beyond systems while incorporating liturgy, midrash & mythopoesis into a personal mythic Judaism?