This word for "rain" refers to one in late fall or early winter. Rainbows in winter are associated with "niji-kakurete-miezu".

This is the 58th of the so-called 72 climates, part of the ancient calendar. It's the first climate of "koyuki", one of the 24 seasons, and lasts for a total of five days.

It's said that the character for "heaven" used to refer to a person's head, taking the character for "big" (which represents a person viewed from the front) and adding a line on top to represent the head. 大 → 天

According to the very oldest radical dictionary named "Shuowen Jiezi", this line symbolizes the heavenly realm above the sky.

To become a "deva" means to surpass humanity and become a being without limits.

Here, deva is written as "summit". Metaphorically, it means the laws that govern the world itself.