Delhi gets driest August in 16 years

The month of August ended with 41.6mm of rainfall for Delhi, translating to a deficit of 83% from the normal of 247.7mm for the month, making it the Capital’s driest August in 16 years, data from India Meteorological Department (IMD) showed on Wednesday.

The month of August ended with 41.6mm of rainfall for Delhi, translating to a deficit of 83% from the normal of 247.7mm for the month, making it the Capital’s driest August in 16 years, data from India Meteorological Department (IMD) showed on Wednesday.

(Hindustan Times)

According to a separate analysis of IMD’s gridded data by HT, which has a slight variation from the numbers the department releases, Delhi’s rain deficit for August was 81% and the Capital recorded the ninth lowest volume of precipitation in August since 1901. As per this data, the amount of rain received this month was the lowest since 2006.

This meant citizens spent most of the month in hot and humid conditions.

At fault was a monsoon trough, a band of the cloud system where rain is active, that was stuck more southwards. “The monsoon trough was mostly over Central India and did not remain close to Delhi for more than one or two days. Even then, the proximity to Delhi was not much and it simply passed over the region,” said a Met department official, asking not to be named.

Overall, the monsoon rain across the country as an aggregate was normal, with the number for August being 3.4% excess. But this number hides wide variations, especially in the paddy belt of the Indo-Gangetic Plains that remained mostly dry.

During August alone, there was a 26.5% deficiency over east and northeast India; 18.2% excess over central India and 27% excess over south Peninsula. At the end of the third month of the monsoon, west and east Uttar Pradesh continued to record 44% rain deficiency, Bihar recorded 38% deficiency, West Bengal 29% and Jharkhand 27%.

These numbers, including the excess rains, signal a meteorological problem that is very likely to lead to significant economic impact by hitting farm yields. The June-September monsoon season waters nearly 60% of the country’s net-sown area. India recorded the hottest March this year. This cut winter wheat production, officially estimated to be the lowest in three years at 106 million tonne.

“We had forecast normal rain in August between 94% to 106% which we have met. We had also forecast that there will be deficient rain over east and northeast India which was seen this month. In terms of agriculture, east UP is expected to be impacted. West UP also has high deficiency but they have irrigation facilities in some areas. Bihar continues to have high deficiency but the rain deficiency over Gangetic West Bengal and Jharkhand has recovered a bit,” said M Mohapatra, director general, IMD.

During the month, it rained on 16 days in Delhi but none of these were in the moderate or heavy category – the most was 8.8mm recorded between August 5 and 6.

Normally, the city is meant to record 247.7 mm of rain in August, its rainiest monsoon month. But this year, the quantity of precipitation made it seem like it was not a monsoon month at all.

In the 1961-2010 period, the lowest average for any of the four months of the monsoon (June-September) was 60.3 mm for June, which is higher than August 2022’s. In Delhi, monsoon onset typically happens at the end of June.

While Delhi’s deficit this August is the highest among all states and union territories, it was not the only dry region. For the 33 states and Union territories for which this calculation is possible using IMD’s gridded data, 19 have a deficit compared to the 1961-2010 average, and 13 have a deficit bigger than 20%. Among the states with a surplus, only nine– all located in western, central, or southern India – had a surplus more than 20%, which is classified as “excess” rainfall by the IMD.

To be sure, the gridded data from IMD might differ slightly from IMD’s published statistics because it summarises data for grids bounded by two latitudes and longitudes 0.25 degrees apart and also imputes some values based on data from neighbouring weather stations to generate a time series. The broad trends seen in the gridded data are, however, the same as in IMD’s published statistics.

Government data has shown an impact playing out on India’s farms already. Acreage of summer rice has shrunk nearly 6%, as on August 26, while sowing of pulses, considered essential commodities, was down 5.2% till the same date, as compared to the same period a year ago.

This means India’s food output is likely to drop for the first time after six straight record harvests. The patchy rains were preceded by extreme weather, which dented sowing, and a particularly dry March. A drop in yield is likely to fan inflation, which will create a significant headwind for the economy.

Meteorologically, the outcome was the result of several factors, Mohapatra explained. “Four depressions formed in August, two over Arabian Sea and two over Bay of Bengal, but none of them moved towards Gangetic Plains. The monsoon trough (a zone of active rain) remained south of its normal position throughout the month, leading to excess rain over central and peninsular India. There were floods over Odisha, Madhya Pradesh, Rajasthan during this period when the low-pressure systems moved over central India. In fact, both in July and August, the monsoon trough has remained south of its normal position leading to deficient rains over Gangetic plains.”

Experts now believe there may not be any significant spells of rain in the near future. “During the first 10 days of September, we do not expect active monsoon conditions. There will be isolated rain over central and northwest India but after that a low pressure system may form. Monsoon is likely to end with normal rains over 100% of the long period average,” said Mahesh Palawat, vice president, climate change and meteorology, Skymet Weather.