Page "Geography of Vietnam" Paragraph 18

Vietnam in the northern regions have a humid subtropical climate, with humidity averaging 84 % throughout the year.

However, because of differences in latitude and the marked variety of topographical relief, the climate tends to vary considerably from place to place.

During the winter or dry season, extending roughly from November to April, the monsoon winds usually blow from the northeast along the China coast and across the Gulf of Tonkin, picking up considerable moisture ; consequently the winter season in most parts of the country is dry only by comparison with the rainy or summer season.

During the southwesterly summer monsoon, occurring from May to October, the heated air of the Gobi Desert rises, far to the north, inducing moist air to flow inland from the sea and deposit heavy rainfall.

The climate in the southern regions especially Ho Chi Minh City and surrounding Mekong Delta is predominantly Tropical savanna climate with high humidity and a distinct wet and dry season.