Vietnam is in Northern hemisphere with tropical monsoon type climate. From October to March, the winter monsoon winds comes from the northeast, bringing chillier temperatures to the provinces from north of Nha Trang, but dry and warm temperatures to the south. From April to October, the southwestern monsoon brings warm, humid weather to the whole country except for those areas sheltered by mountains, such as coastal lowlands and Red River Delta. Northern Vietnam has cooler season, with occasional frost and snow on the highest northern mountains. In the southern Vietnam, the lowlands are sheltered from outbreaks of colder northerly air and the dry season is warm to hot with much sunshine. Vietnam has a single rainy season (May-September) that brings abundant rainfall; with rain infrequent and light during the remainder of the year. You can visit Vietnam any time of the year, always finding sun somewhere. The high tourist season is from October to March, though disruptive storms might occur in the center of the country from September to December. The best time for the central coast beaches is between May and August, and autumn is the best time to find clear sky in Ha Long Bay.