Visitors to Ho Chi Minh City during the month of May should plan on bringing a raincoat since it will be raining some days. This month is part of the rainy season. May is the hottest month. The average maximum temperature lies around 33.0°C (91.4°F). During the night it can be very warm as well. With a water temperature of around 30.0°C (86°F), this is a great month to swim. You will see the sun sometimes in this month, it has 124 hours of sun.