Major mountain ranges around the world generally exhibit a linear or arc-shaped alignment, often running parallel to continental margins or forming along ancient plate boundaries. Prominent examples include the North-South orientation of the Andes and Rocky Mountains, and the East-West alignment of the Himalayas, Alps, and Atlas Mountains, primarily formed by convergent plate tectonics.

These formidable geological features profoundly influence local weather conditions in several critical ways:

1. Orographic Effect and Rain Shadow: The most significant impact is the orographic effect. As moist air currents encounter a mountain barrier, they are forced to rise, cool, condense, and precipitate heavily on the windward side. Once over the peak, the now drier air descends on the leeward side, warming adiabatically and creating a distinct rain shadow. A classic example is the Western Ghats in India; its western slopes receive abundant monsoon rainfall, while the eastern Deccan Plateau lies in its rain shadow, experiencing significantly lower precipitation and semi-arid conditions. Similarly, the Cascade Range in the USA creates the arid Columbia Basin to its east.

2. Temperature Modulation: Mountains act as significant climatic dividers. Higher altitudes inherently lead to lower temperatures. Crucially, they can block or channel air masses. The towering Himalayas, for instance, prevent frigid Siberian winds from sweeping into the Indian subcontinent during winter, contributing to a milder climate for the region.

3. Wind Patterns: Mountains can also funnel winds, increasing their speed through passes, or generate specific local winds. Warm, dry downslope winds like the Chinook winds in the Rockies (North America) or Föhn winds in the Alps (Europe) occur on the leeward side as air descends and warms, leading to rapid temperature increases and snowmelt.

In essence, the alignment and sheer mass of mountain ranges create unique microclimates and significantly alter regional weather patterns, shaping ecosystems and human habitation.