Cyclone Season

Cyclone season: April to December is the cyclone season but over 65% of all cyclones occur in the last four months of the year.

Cyclones and Anticyclones

Bay of Bengal receives the remnants of major cyclones (typhoons) from west Pacific Ocean. And, most of the typhoons in west Pacific in northern hemisphere form between June and November, rather than April-May. So Oct-Dec period in India receives majority of cyclones from both in-situ developed cyclones and remnants cyclones from west Pacific Ocean.

The another reason that more cyclones strike in October is that wind shear — the difference within wind speeds and direction at two different levels — is low during this time. Low wind shear, when combined with surface sea temperatures greater than 26°C, raises the likelihood of cyclones. In monsoon season, cyclones are rare because of high wind shear.

  • The cyclones in the northern hemisphere rotate anti-clockwise.
  • They derive their strength from the moisture in waters such as the Bay of Bengal and move west, inclined in a northerly direction and peter out into the sea or land, depending on their origin.
  • On its way to diminish, sometimes, if cyclone gets a sort of second wind by deflecting right or eastwards, then it is known as re-curving cyclones.
  • This happens due to air currents in the local atmosphere that push cold air from the poles towards the equator and interfere with cyclone formation.
  • In the southern hemisphere, the cyclones spin clockwise and therefore also re-curve in the opposite direction