Hi there! I lived in HCMC for a year august/september is still the rainy season, but it’s not the worst of it (buy raincoats and keep them on you!). Downpours happen without much notice but they don’t last long. The south is hot, no matter what month you go (I found Nov/Dec to be the ideal months). As far as a place to stay, District 1 is the place…more specifically, Bui Vien and Pham Ngu Lao area (aka. backpacker district). How much is your budget per night?