Wind direction in purple shows away-going flows directed towards a likely low-pressure area developing over extreme eastern parts of Bay of Bengal, which is unhelpful for timely monsoon onset over Kerala. | Photo Credit: www.windy.com

Arrival of the south-west monsoon appears to be slipping slightly, if signals from the Bay of Bengal and the Arabian Sea are any guide. Sri Lanka, the immediate prior port of call before the monsoon reaches Kerala, said this (Monday) morning that the season is only ‘gradually establishing across the island.’

The update suggests the onset over the island is now delayed beyond its normal date of around May 22. From here, the monsoon could take up to a week to reach Kerala. After advancing over Myanmar and the Andaman and Nicobar Islands broadly on schedule, the flow appears to have lost some of its early momentum.

Lull in progress

Myanmar’s Department of Meteorology and Hydrology too has indicated a lull in the monsoon’s northward progress after its onset over the southern parts of the country. Its advance into central Myanmar is now expected to be delayed by two to four days, according to latest available projections.

In this manner, loss of pace upstream now appears to be echoing farther west and south-west, disrupting the monsoon’s progression toward Sri Lanka and, subsequently, Kerala. The Sri Lankan Met Department said it sees an increase in rainfall over the southwestern parts of the island nation during next few days. 

Unfavourable winds

Fairly strong monsoon-friendly winds about (30-40) km/hr can be expected at times over western slopes of the central hills, Northern, North-central, North-western and Southern provinces and in Trincomalee district. But winds are currently unfavourable as they blow unorganised and weak across the Kerala coast, just to the north.

Given these signals, it now appears likely that the onset over Kerala could fall toward the latter half of India Meteorological Department’s (IMD) onset window of May 26 with a margin of plus or minus four days. A likely low-pressure area developing over extreme east Bay of Bengal during this period could draw monsoon flows away, though it may help the monsoon establish with a delay over Sri Lanka first.

Published on May 25, 2026