Monsoon Magic at Mesmeric Cherrapunjee

The micro-climatic conditions in and around Cherrapunjee, that is estimated to cover 100 to 200 square km, has been classified by meteorologists as follows:

Period Months
Pre-monsoon months March, April, May 
Monsoon months June, July, August, September
Post-monsoon months October, November, December
Winter months January, February

Cherrapunjee gets the Bay of Bengal arm of the Indian Summer Monsoon. The monsoon clouds fly unhindered over the plains of Bangladesh after they cross over to land. After about 400 km of traveling over land they are confronted by fortress wall like Khasi hills, which abruptly erupt out of the plains to reach a height of about 4500 feet above MSL within a short distance of 2 to 5 km. The orography of the hills with many deep valleys, acting like funnels to channel the low flying moisture laden clouds (500-1000 feet) help clouds from a wide area to converge over Cherrapunjee. Cherrapunjee falls directly on the middle of the path of this stream of southwest monsoon.

The monsoon winds push the rain clouds through these gorges and up the steep slopes. The rapid ascendance of the clouds into the upper atmosphere hastens the cooling and helps water vapour to condense into water. Most of Cherrapunjee’s rain is the consequence of air being lifted as a large body of water vapour. The process of condensation is greatly helped by the cold wind blowing from the Himalayan range from east / northeast to south in the upper atmosphere as they meet over Cherrapunjee, the upward thrusted moisture laden monsoon air stream, deflected by the perpendicular South Khasi Hills.

In Cherrapunjee you get to see rain coming in a slant with such velocity that one can be drenched in no time. Occasionally cloudbursts can occur in one part of Cherrapunjee whereas other areas may be totally or relatively dry. Atmospheric humidity is so high during the peak monsoon period that water vapour condenses into water droplets on the hair, eyebrows and moustache. The high humidity during the monsoon months causes clothes, books etc. to become damp and get molded. Books come off their binding. Clothes get black spots due to moulds. Films get stuck to each other. Moisture creeps into framed photographs and soon the photos start fading from the corners. It becomes difficult to dry clothes due to lack of sunshine. At present only a few cloth dryers are around here. Common people put a charcoal fire under an upturned bamboo basket (called polo) and spread the damp and wet clothes on the top of the basket to dry.

A perusal of the rainfall data of Cherrapunjee over the years reveals that the first pre-monsoon showers arrive at Cherrapunjee by the 10th March every year. These pre-monsoon showers are called Nor’Westers because they appear to come from the northwest direction. The gap between rainy days start shrinking as one proceeds from March to May. The days preceding rains progressively become warmer and the temperature takes a dip after the showers. By May the rains become frequent. These pre-monsoon showers are a severe type of thunderstorm that occurs around this region, accompanied by strong squalls. They are called ‘Kal Baisakhi’ in Bengal and ‘Bordoi shila’ in Assam. They are mainly experienced during the hot months from March to May, but they are sometimes experienced in the latter half of February and in the first half of June. They cease to occur after the Southwest monsoon sets in by June.

June and July can have continuous spells of rain lasting a few days to a couple of weeks or more. Sometimes you cannot see the sun for a week or more. However, in these two months one can have continuously no rain days for a week too. At Cherrapunjee one can have a few days every year having more than 300 mm of rainfall in 24-hour period. Sometimes it rains upwards of 500 mm. That is to say that quite a few days every year at Cherrapunjee get 50% to 80% of the annual rainfall of London or Paris in just 24 hours.

In 2020, we had received on 11 days more than 300 mm of rainfall in 24 hours – of which on three days, we received over over 500 mm of rainfall. The total rainfall received in these 11 days was 4620.2 mm.

It had rained 1563 mm on 16th June 1995. The internationally accepted rainfall-reporting format in four digits including one decimal digit proved inadequate on that day. On 19th July 2004 it rained 793.2 mm; on 26th June 2012 it had rained 772.2 mm and on 17th June 2017 it had rained 638.2 mm in 24 hour periods.

The beauty of these heavy rainfall days is that, the place does not get flooded and the deluge drains off to Sylhet flood plains in Bangladesh. Waterfalls grow big. It is so mesmerising to see the enchanting beauty of this place then, with the clouds floating leisurely through the valley. The whole place becomes alive with the humming, chirping and singing of the insects and birds and the thundering sound of the raging rivers at the bottom of the valley.