Succinct
He asked for THE REASON
The cosmic ambient that affects weather is the same as the ambient that affects the conception and nativity.
Many have stumped upon this doctrine, since the time of Cicero, and ask why should we not follow the °C at the time of birth, or the winds, or the rain etc. rather than the distant planets. We answer that the reason for this is that the current weather is dependent upon many other things, like geographical place, the season and the syzygy preceding the tropic, the month with the preceding new or full moon, and the day, and the hour etc., while the nativity is most affected by the exact current ambient, which although does not exercise preponderating effect upon the weather, for example the rising of Mars every day does not cause hot weather, but this is due to the fact of the higher aforementioned beginnings of the universe, where as the rising of Mars does indeed cause hot temperament and body of the nativity, since in some sense, the ambient does afflict preponderating influence upon the current environment, and likewise to the nativity, since it is an event and a beginning spanning seconds of time in that exact environment.