Travelling to Hanoi for a week in April....what to wear???

I have never been to Vietnam, travelling to Hanoi for the first week of April from Melbourne and I have no idea what to pack to wear??!! From what I get it is raining a lot, the weather seems to be in the high teen- low twenties.....do I need to bring warm clothes, coat, denim jeans etc or will the humidity cause it to be warm? Any advice would be greatly appreciated! Thanx

You should really post this in the Asian section.