India's seasonal rainfall pattern is dominated by the monsoon, which generally arrives at the SW coast in late May or June, covering most of the country by the beginning of July, and retreating in October. However, the popular image of the monsoon is misplaced. Even in the wettest areas - the west coast or the NE hills of the Shillong plateau - there are periods of days at a time when it does not rain. Elsewhere the rainy season is marked by prolonged very heavy showers, interspersed with cloudy, humid weather and occasional bright patches.