微雨 is read as びう (biu) and means light rain.
びう
biu
びみょう
not great
ほおえむ
to smile
びしょう
smile
びねつ
slight fever
びせいぶつ
microbe
microscopic
びどう
slight movement
びりょう
minuscule amount
びさい
minute
かすか
poor
びしん
slight earthquake
びりょく
little power