Monsoons in Thailand
Monsoon Waterfalls at Tak Thailand
Thailand receives two monsoons each year.
The Northeast Monsoon
- The Northeast Monsoon comes from the Western Pacific Ocean and brings heavy rain from November to April through out. Accordingly the Gulf of Thailand then receives heavy rain and winds. During this period the sea in the Gulf of Thailand has strong currents and poor under water visibility. This is not a good time to go scuba diving in the Gulf of Thailand. However during this same period on the other side of the Peninsula on the Andaman Coast the water is clear and not turbulant. Then visibility is 30 meters and the sea calm. The Andaman Sea does not suffer any monsoon wind or rain during this period.
- The Southwest Monsoon is the reverse of the Northeast Monsoon and comes to Thailand from the Indian Ocean from May to October and impacts the Andaman Coast. Then the sea waters of the Andaman Coast are disturbed whilst those of the Gulf of Thailand on the other side of the Peninsula are calm and clear for diving and boating.
How Monsoons work in Asia and affect Thailand
A seesawing ocean
- '' During the summer, the huge landmass of Asia heats up like a brick in the sun; hot air rises over the continent, and cool ocean air, filled with moisture, flows in to replace it. During the winter, the air over the Indian Ocean is warmer than the air over land; the ocean air rises, drawing cool dry air from Asia out to sea.
- The size of the air mass that Asia breathes in depends, in part, on the temperatures of the Pacific and the Indian Oceans. And the temperatures of these oceans are influenced by two large-scale, dynamic patterns of winds and water temperatures that seesaw between two extremes: El Niño-Southern Oscillation (or ENSO) and the Indian Ocean Dipole.
- During “normal” years in the Pacific Ocean, trade winds blow along the equator from Central America toward Indonesia, pushing warm surface water toward the western Pacific. In the eastern Pacific, cool water from the deep ocean is pulled up to the surface to replace the water blown to the west. The constant blowing of the trade winds maintains a Pacific Ocean whose surface is tilted. So much warm water piles up in the west, the sea surface height there is about 7 inches higher than in the east.
- Occasionally, the trade winds will weaken just for a bit. Without the trade winds holding the mound of warm water in place, it begins to slide back to the east. This is an “El Niño” event. As the pool of warm water from the western Pacific spreads eastward across the Pacific, it creates a cap of warm water in the east, effectively preventing the cool deep water from reaching the surface.