Saigon is a hot city. If you have plans to visit it, bring plenty of Summer clothes. T-shirts, shorts and a good pair of sandals will be your best allies. You will also need a raincoat. Remember that when visiting pagodas and temples you should not show much skin.
The best time to visit the city is late in the afternoon. At this time you will be surrounded by locals when walking along the streets in downtown Saigon. At first hour in the afternoon, you will only see foreigners in the streets. People of Saigon, specially women, avoid the sun. They even use masks and long gloves to protect themselves from the sun rays. Dark skin is not fashionable.