Appropriate dress differs from North to South. Southern Vietnam is tropical year round and people dress comfortably and casually. Lightweight cotton and wool fabrics will be comfortable at any time of year. While they may resist wrinkles, synthetics and are blends miserably hot. Generally, short pants are inappropriate anywhere but a beach resort or a farm and you will look like a foolish tourist on the streets of most cities. Jeans are almost always fashionable except for business occasions.