Expliquer Moi Why Does The Onset Of Rain Bring About Such Frequent Power Cuts?

My best guess is that at most of the places, the lines & joints are lower quality. It's true that most of the power cuts happen during of just after the rains, but they do happen when there are strong winds. From what I've seen - the rains and storms cause short circuits and make the CBs or transformers trip. That leads to power failures.

Okay, but there are times when they power outage lasts for a very short period of time. It's off for a few minutes, and then it's back on. Wouldn't think that's power failure. A precautionary measure perhaps? Why, exactly?

What K says about old joints (especially with missing enclosure covers) causing problems when wet and high winds contributing to shrts is valid.
In Bangalore most of the domestic distribution is using archaic overhead uninsulated cables. I have seen many cases of crows and bats blown between two cables by the winds leading to tripping. There is also the issue of summer storms that come with a roaring wind. The cables themselves have become longer between the poles due to the heat. Often the poles are out of perpendicular contributing to even more slack. Nearby trees wave their branches in the wind momentarily shorting cables and causing CBs to trip.

Routine maintenance of the distribution system is never done. It is always breakdown maintenance. Since this is done under difficult conditions such as in rain and usually in poor illumination witha wobbling torch light, this is rarely done well.
'Chalti ka naam gaadi'

India Shining, well flickering mostly.