The three principal mechanisms by which moist air is lifted, cooled to its dew point, and made to release precipitation: convectional, orographic (relief), and cyclonic (frontal) rainfall.
- Convectional rainfall: intense surface heating makes air rise, cool, and condense; gives heavy afternoon downpours, often with thunder, typical of equatorial regions and the Indian summer.
- Orographic (relief) rainfall: moist air is forced to rise over a mountain barrier, giving heavy rain on the windward side and a dry rain-shadow on the leeward side; Mawsynram and Cherrapunji (Meghalaya) and the Western Ghats coast are classic examples.
- Cyclonic (frontal) rainfall: rain from the meeting of warm and cold air masses along a front, common in temperate latitudes and from tropical cyclones; western disturbances bring this type of winter rain to north-west India.
- The rain-shadow effect is why the Deccan interior, behind the Western Ghats, is comparatively dry.
- Precipitation also occurs as snow, hail, sleet, and drizzle depending on temperature.
The three rainfall types with examples, the windward versus rain-shadow contrast, and the link of orographic rain to Cherrapunji and the Western Ghats are recurring assertion-reason and matching items.
Convectional (heating, rising air) versus orographic (mountain barrier) versus cyclonic (fronts and depressions); windward (heavy rain) versus leeward (rain shadow, dry); the Deccan interior is dry because of the Western Ghats rain shadow.
Rain forms three ways: convectional (heating), orographic (mountains, with a rain shadow), and cyclonic (fronts and depressions).