What is the primary factor responsible for the heavy annual precipitation and dense cloud cover experienced across most parts of Sikkim during the monsoon season?

💡 Solution & Explanation

Sikkim receives abundant rainfall primarily due to the South-West Monsoon winds, which carry moisture from the Bay of Bengal and strike the steep Himalayan mountain ranges, causing heavy orographic precipitation. Westerlies primarily affect northern India during winter, while north-east trade winds are largely dry over this region. Orographic uplift cools the moisture-laden air rapidly, producing dense fog, frequent cloudbursts, and heavy downpours across the valleys and ridges of Sikkim throughout the summer months.