When more than two things are being compared, the superlative (most) is needed. The fact that ALL weather phenomena are being taken into account (we can assume this means more more than just two things), most is appropriate rather than more. Choices A and C contain more and are eliminated. Choice B is terribly awkward, as is E, which seems to go beyond the issue of all weather phenomena. Choice D then, is the best answer.
"Start By Doing What Is Necessary ,Then What Is Possible & Suddenly You Will Realise That You Are Doing The Impossible"