My Suggestions

ĩhakuhĩ

adv.

  1. near, about to. Near; about to. Indicating temporal or spatial proximity, especially the imminent beginning or onset of an event such as the rainy season.

Example: Nigũo ũgĩe na kĩambĩrĩria kiega gĩa mĩmera tĩgĩrĩra wa handa mbura ĩhakuhĩ kura (To have a good start for the banana plants, planting should be timed to coincide with the on-set of rains.); ĩka maũndũ maya mbura ĩhakuhĩ kuura; (Should be done at the onset of rains.); Ihinda rĩega makĩrĩa rĩa kũhanda marigũ nĩ rĩrĩa mbura ĩhakuhĩ kura (The best time to plant bananas is at the onset of the rainy season.)