Final answer:
Prevailing winds bring wet weather primarily when they carry moisture from oceans and rise due to geographic features like mountains, causing precipitation on the windward side. This process is evident in heavy rainfall during monsoons in South Asia and the orographic precipitation on the western coasts of islands. Additionally, atmospheric phenomena such as tropical storms can lead to significant wet weather due to prevailing winds.
Step-by-step explanation:
Prevailing winds bring wet weather when they carry moist air from over the oceans and encounter obstacles such as mountain ranges that force them to rise. This is due to the process of orographic lift, where the moist air from the ocean rises up over a mountain range, cools, and its water vapor condenses, leading to precipitation on the windward side. Conversely, when these winds descend on the leeward side, they create a rain shadow effect, resulting in drier conditions.
Examples of this would include the heavy rainfall on the western coasts encountered by the prevailing westerly winds on islands, especially when they interact with the Southern Alps, as well as the monsoon rains in South Asia which bring moisture to the region when moisture-laden clouds are forced to rise by the Himalayas. However, after the monsoon season, regions can experience a cooler and drier period with the onset of dry monsoon winds, such as the northeast monsoon in South Asia from November to February.
In addition to the orographic effect and monsoons, tropical storms also bring wet weather when atmospheric pressure drops significantly, resulting in increased wind strength and precipitation. Thus, prevailing winds bring wet weather when they are laden with moisture and are forced to rise by geographical features or when they are part of large storm systems.