风 (fēng): Wind.
雨 (yǔ): Rain.
过后 (guòhòu): After passing. This is a compound of `过 (guò)` meaning “to pass” or “to cross,” and `后 (hòu)` meaning “after” or “behind.”
见 (jiàn): To see, to witness, to appear.
彩虹 (cǎihóng): Rainbow. This is a compound of `彩 (cǎi)` meaning “colorful” and `虹 (hóng)`, the specific character for “rainbow.”
The characters combine literally to describe a meteorological event: “Wind and rain pass, see a colorful rainbow.” Metaphorically, the phrase constructs a powerful narrative: enduring the storm (风雨) of life's challenges is a prerequisite for seeing the beauty and reward (彩虹) that follows.