Page 2 - Lesson notes-Wind Formation
P. 2
Winter Monsoon winds:
During winter season, dry and cold air blows from colder North-east region of the land to the
ocean. These winds cause rainfall in coastal regions are called as winter monsoon winds.
Winter monsoon winds are also called as North-east monsoon winds. It causes less rainfall as
compared to the summer monsoon winds.
Scientific Concepts:
Concept Explanation
Wind Moving air caused by differences in temperature and pressure.
Hot Air Lighter, rises up.
Cold Air Heavier, sinks down.
Air Air exerts pressure. Hot air has low pressure; cold air has high pressure.
Pressure Wind moves from high to low pressure.
Temperature Comparison: Land vs Water
Land Sea
Condition Result
Temperature Temperature
Summer Very hot (35–45°C) Moderate (25–30°C) Land heats quickly → air rises
Day → sea breeze
Winter Cool (10–15°C) Warmer (20–25°C) Land cools quickly → air sinks
Night → land breeze
Wind Movement Patterns
• Wind doesn’t move straight north-south due to Coriolis Effect (caused by Earth’s rotation).
• Example: In India, monsoon winds come from south-west (summer) and north-east (winter).
Monsoon Rainfall Data (India)
Type of Monsoon Months Rainfall Contribution
South-West June to September ~75% of annual rainfall
Monsoon
North-East ~15%
Monsoon October to December (Mainly affects Tamil Nadu, Andhra Pradesh)
