Well, if you are going to ask them about the unpredictable rainy weather in the Philippines. You would want to ask, "Kamusta kayo ngayong tag-ulan?" (How are you coping with the rainy season?).

When you asked a person "How are things?" or in translation "Kamusta ang mga bagay-bagay?" They may answer what is happening to them in general like "Fine." or "Ayos lang." In your case, you wanted to know if they are alright despite the rains, you say "Kamusta ang lagay ng panahon diyan sa inyo?" Are you trying to express your concern? You may add this, "Ayos lang ba kayo?"

you might want to ask "how are things going?" it's translation would be: "kumusta ang mga bagay-bagay?". literally, you're simply asking one's present condition but "bagay-bagay" here would imply many things you want to know about someone.

o genki desu ka? ~> " how are this? " how are you? ~> musta? / kumusta ka ??

we usually just say "kamusta" or "kumusta"?