Onset of the northeast monsoon:
The timely onset of the northeast monsoon in October 2025 has brought much-needed relief to Tamil Nadu and Andhra Pradesh, regions that rely heavily on it for both agriculture and water security.
- Northeast Monsoon (October to December): As the southwest monsoon (June to September) begins to fade, the northeast monsoon sets in by October.
- This is also called the retreating monsoon. It is shorter and less widespread but still important, especially for southern India.
- By October, the land starts to cool faster than the ocean. This creates a high-pressure area over the Indian subcontinent and a low-pressure area over the surrounding seas.
- The direction of wind flow reverses and winds blow from land to sea.
- These are called northeasterlies.
- Since these winds pass over the Bay of Bengal before reaching the southeastern coast, they pick up some moisture.
- As they reach Tamil Nadu, south Andhra Pradesh and parts of Sri Lanka, they provide abundant moisture for rainfall activity.
- This rain is crucial for regions like Tamil Nadu that do not receive much during the southwest monsoon. It supports rabi crops and replenishes reservoirs in the southern peninsula.
