SSC CGL Geography · Climatology, Atmosphere and Weather
Pressure, Winds and Storms
What drives the monsoon (the ITCZ, the jet streams and the Tahiti-Darwin pressure gap), the retreating monsoon, and India's local winds and storms with their names.
Why this matters
Sixteen questions in the bank: six from the 2023 shifts, nine from the 2024 shifts and one from the 2025 shifts, 12 of them EASY. Most give a wind or shower and ask where it blows or what it does, so a table of local winds is the heart of the page.
Concept 1 of 2: What drives the monsoon
Definition
The features:
- ITCZ (Inter Tropical Convergence Zone): it moves north with the sun, and in July it lies at about 20 to 25 degrees N over the Gangetic plain, as the monsoon trough.
- Easterly jet stream: in summer it blows over the peninsula at about 14 degrees N.
- Tahiti and Darwin: the pressure difference between them forecasts the monsoon. If it is negative, expect a below-average and late monsoon.
The retreating monsoon (October and November):
- High pressure replaces the low over the northern plains, so skies clear.
- Hot, humid days follow, called October heat.
- The north-east monsoon brings rain to Tamil Nadu, Kerala and coastal Andhra Pradesh from October to December.
Wind speed is measured with an anemometer, first described around 1450.
Practise this conceptself-check · 3 quick reps
The same idea in a real exam question:
Example 1 · Climatology, Atmosphere and Weather · Pressure, Winds and Storms
Negative means a weak monsoon
Concept 2 of 2: Local winds, showers and storms
Definition
Local winds and showers:
- Loo: a hot, dry, dusty wind over the north and north-western plains (Rajasthan, Punjab, Haryana, Uttar Pradesh) in May and June.
- Nor'westers: violent evening thunderstorms of Bengal and Assam, called Kalbaisakhi in Bengal.
- Mango showers: pre-monsoon rain in Kerala and Karnataka that ripens mangoes.
- Blossom showers: pre-monsoon rain that makes coffee flower in Karnataka.
- Western disturbances: winter storms from the Mediterranean that bring rain and snow to the north-west.
Cyclones:
- The calm centre of a cyclone is its eye.
- Tropical cyclones are called hurricanes in the Atlantic, typhoons in the western Pacific, cyclones in the Indian Ocean and willy-willies in Australia.
Practise this conceptself-check · 4 quick reps
The same idea in a real exam question:
Example 2 · Climatology, Atmosphere and Weather · Pressure, Winds and Storms
Mango showers are not Nor'westers
Summary — formulas & gotchas at a glance
A revision cheat-sheet for the formulas and gotchas above. Click any concept name to jump back to its full explanation.
Reference tables (2)
What drives the monsoon5 rows
Watch out for (2)
- Negative means a weak monsoon→ What drives the monsoon
- Mango showers are not Nor'westers→ Local winds, showers and storms
Test yourself on Climatology, Atmosphere and Weather
15 past SSC CGL questions from this chapter, timed at 9 minutes and marked the way the exam marks it. You see your score and every answer the moment you finish. Free to start.