"The rain subsides." should be accepted. The present perfect tense for English implies Ua before mao.

Shouldn't "it's stopped raining" the same thing?

New Hawaiian Dictionary

Link: https://manomano.io

mao

[PE] 1 vsCleared, as rain; alleviated, assuaged, as grief; to clear up, as rain; to pass, as sadness. Ua mao aʻela ke kaumaha, the sadness has ceased. [PPN mao]