Pre-Monsoon Storms Over Indian Seas

Key Takeaways:

• Indian seas have two primary cyclone seasons: pre-monsoon and post-monsoon.
• Bay of Bengal sees higher storm frequency compared to the Arabian Sea.
• Historical data (2015–2025) shows limited April activity, especially over the Arabian Sea.
• Early signals hint at a possible Arabian Sea system around May 10, though confirmation is pending.

Indian seas have predominantly two stormy seasons: Pre-Monsoon (March–May) and Post-Monsoon (October–December). Otherwise, cyclonic storms can form in any month, but the frequency is very small. During the monsoon months, between June and September, there are occurrences of cyclonic storms, more so in the starting month of June and the closing period of September.

In the month of March, storms do not form in the Arabian Sea, and these are far and few in the Bay of Bengal as well. Over the Bay of Bengal, they usually originate between 5° and 8°N, move in a westerly or northwesterly direction, and strike the north Tamil Nadu coast or the east coast of Sri Lanka. They have a tendency to weaken and dissipate over the sea area in the course of their movement.

In April, most of the Bay storms originate between 8° and 13°N and east of 85°E. Their direction of movement is initially towards the northwest or north; later, they recurve towards the northeast and strike the Arakan coast of Myanmar. Some of these freak storms do strike the Odisha or West Bengal coast. The number of storms in the Arabian Sea is far less than over the Bay of Bengal. Their movement is similar to the storms in the Bay and occasionally recurves to strike the Gujarat–Sind Makran coast.

There is an appreciable increase in the frequency of storms from April to May. Most of the Bay storms originate between 10° and 15°N, move initially in a northwesterly direction, and then recurve towards the northeast. The whole of the east coast of India, the coastal areas of Bangladesh, and the Arakan coast of Myanmar are liable to be struck by these storms. In the Arabian Sea, the storms move northwest towards the coast of Arabia. A few move in a northerly direction or recurve to head for the Maharashtra–Gujarat coast.

Between 2015 and 2025, a total of ten cyclonic storms formed in the Indian seas during the pre-monsoon period. In 2015, 2018, and 2025, no storms formed in the Indian seas. Also, no storm formed in the month of April over the Arabian Sea during this period. The Bay of Bengal hosted two storms, one each in April 2017 and April 2019. The 2019 storm Fani was extremely severe and struck Odisha near Puri on 03rd May 2019. In the month of May, eight storms formed over the Bay of Bengal and only one over the Arabian Sea between 2015 and 2025. Amphan was the only super cyclonic storm in the pre-monsoon season during this period, which struck West Bengal near Bakkhali on 20 May 2020. The Arabian Sea had an extremely severe cyclonic storm, ‘Tauktae’, which struck the coastline between Diu and Una (Gujarat) on 17th May 2021.

This year, no storm formed over the Indian seas in the months of March and April. There are very preliminary indications of the likelihood of a storm coming up over the Arabian Sea. This will be an exception to the earlier track record of the Arabian Sea. Though it is too early to share any authentic information as of now, a vortex may come up sometime around 10th May in the equatorial region of the Southeast Arabian Sea. Confirmation will need another 48–72 hours. Such storms invariably head for the Somalia coast near the Horn of Africa.