Monsoons are seasonal winds that bring long wet spells to many tropical regions.

The longer version

Monsoon circulation is driven by the uneven heating of land and ocean across the seasons. In summer a continent warms far more than the sea beside it, air rises over the land, and moist ocean air is drawn inland to take its place.

That inflow delivers long spells of rain to tropical regions for months at a time. When the seasons turn, the temperature contrast reverses, the flow flips direction, and a drier period follows. Mountain ranges strengthen the effect enormously by forcing the moist air upward, wringing out far more rain on the windward side than on the sheltered side beyond.

Where this entry sits

Clouds, wind, rain, and storms shape daily life in ways that most people barely notice. This collection explains snow, lightning, rainbows, the turning seasons, temperature, the instruments forecasters rely on, and scraps of old weather lore. The full list sits on the Weather and Climate page, where every entry is listed in order.