Why there is No Cyclones in October?

Cyclone is a general term for a weather system in which winds rotate inwardly to an area of low atmospheric pressure. For large weather systems, the circulation pattern is in a counterclockwise direction in the Northern Hemisphere and a clockwise direction in the Southern Hemisphere.

  • India’s east and west coasts are prone to cyclones with the maximum associated hazards—rain, heavy winds and storm surge— faced by coastal districts of West Bengal, Odisha and Andhra Pradesh. 
  • Cyclones in the North Indian Ocean are bi-modal in nature, that is, they occur during two seasons— April to June (pre-monsoon) and October to December (post-monsoon). Of these, May and November remain the most conducive for the development of cyclones.
  • October to December period is among the favourable months for the development of cyclones in the Bay of Bengal and the Arabian Sea. This year, however, October passed without witnessing a cyclonic storm.
  • IMD officials have attributed it to the weak La Nina conditions along the equatorial Pacific Ocean. Cooler than normal sea surface temperatures over this region—termed as La Nina— has been prevailing since August this year. 
    • Because Madden Julian Oscillation (MJO) was positioned in a favourable phase, the low-pressure systems intensified maximum up to a deep depression. Since the MJO has just crossed the North Indian Ocean region and has moved eastwards, there will be no supportive factors that could influence the formation of cyclones this month.


Madden Julian Oscillation (MJO) is kind of an eastward-moving cyclic weather event along the tropics that influences rainfall, winds, sea surface temperatures and cloud cover. They have a 30 to 60-day cycle.

La Nina is a weather pattern that occurs in the Pacific Ocean. In this pattern, strong winds blow warm water at the ocean's surface from South America to Indonesia. As the warm water moves west, cold water from the deep rises to the surface near the coast of South America.



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