"This is a rainy day."
Translation:He lā ua kēia.
Ua means rain. The while sentance translates to "this day is rainy." He la (a day) (ua) rain (kēia) this. This is how the sentance structure goes with the subject and/or demonstrative at the end. think of the demonstrative (this) to modify the subject of (a day) so what you are saying is this day is rainy or this is a rainy day which is saying the same thing.