South West Monsoon

The people living in the West Coast and South West  of Sri Lanka experience much of rain, from about end of May to end of September each year. This weather pattern prevails due to the South West Monsoons.

These monsoons will be dealt with in the pages to follow, till then a drizzle of explanation will suffice,

The term Monsoon comes from the Arabic “Mausim”, which means seasonal weather or wind shift.

During the Northern summer the continent of Asia gets very warm resulting in low pressure over it. The lowest recorded so far, being about 996 mb ( millibar)over the North West India. This low being considerably lower than the equatorial low of 1012 mb and, hence the pressure gradient exists from the equator towards North West India. The South East Trade winds blowing from oceanic high of the 30 degrees South Latitude  towards the equatorial low and cross over the equator and blow as a strong South west wind called South West monsoon towards the low over NW India.

The period of the year of SW Monsoon the India Ocean – Arabian sea is from about June to September.

Effects :- Brings heavy rain to West Coast of India, West Bengal region, Bangladesh and Myanmar.