Mumbai: A defining aspect of 2023 is the significant shift in rainfall patterns. The late onset of the southwest monsoon triggered heat waves in June. Despite certain regions such as eastern Uttar Pradesh, Jharkhand, and the southern states grappling with an overall rainfall deficit, the monsoon saw a rise in heavy rainfall days compared to 2022. The occurrence of unseasonal rainfall in March, April, and December, primarily attributed to the influence of western disturbances and cyclonic storms, marked a rise in extreme events throughout the year.

In eight charts, we analyse the year’s weather.


Central India recorded over thrice the usual rainfall in March, April

India experienced extreme weather events on 84 of the 120 days in the first four months of 2023, predominantly thunderstorms and hailstorms, according to a compilation of such events by the Centre for Science and Environment. March and April reported elevated levels of rainfall across the country, with Central India experiencing the most significant deviation from the norm.

March 2023 saw the influence of seven Western Disturbances, causing heavy winds and intense rain in the northern and central regions. The weather during March 14-22 was the most severe. In contrast to March 2022, which recorded the highest maximum temperature in March in a century, this year's temperatures exceeded the normal by 0.36 degrees Celsius, due to the rainfall events throughout the nation.


The Union and state governments, including Uttar Pradesh, acknowledged the loss to crops, especially wheat, and relaxed procurement norms to help farmers in April 2023.


In the month of May, northwestern India recorded the third highest rainfall in the last century. The cyclonic storm Mocha formed over the Bay of Bengal during May 9-15. In addition, eight Western Disturbances affected the weather over the country during this month, triggering large-scale thunderstorms and rainfall activities accompanied by lightning, hail storms, squalls and gusty winds in many parts of Northwest India and central India. They were the main reason for below-normal maximum temperature over the region.


Monsoon onset delayed, southern peninsula saw half normal rainfall in June

The southwest monsoon set in over south Kerala and south Tamil Nadu on June 8, 2023 against the normal date of June 1. Rainfall over the country as a whole during the monsoon season (June-September) 2023 was 94% of its long-period average (LPA).

Northwest India (101% of LPA) and central India (100% of LPA) received normal rainfall, while the remaining two regions (91% of LPA for the southern peninsula, 82% of LPA for northeast India) have received below normal rainfall.

In June, most subdivisions in northwest India received excess rainfall, while eastern Uttar Pradesh, Bihar and Jharkhand recorded much lower rainfall. IndiaSpend reported the delay in Kharif sowing due to this, affecting crops like arhar, maize, sunflower, cotton and rice.


Of India’s 36 meteorological subdivisions, Nagaland, Manipur, Mizoram and Tripura, Gangetic West Bengal, Jharkhand, Bihar, eastern UP, south-interior Karnataka and Kerala received deficient rainfall during the monsoon between June and September. According to studies by India Meteorological Department, in the last 30 years, Uttar Pradesh, Bihar, West Bengal, Meghalaya and Nagaland have shown significant decreasing trends in southwest monsoon rainfall.



42% more ‘very heavy rainfall days’ than in 2022

The 2023 southwest monsoon season witnessed several instances of extreme rainfall. In June, Rajasthan experienced exceptionally heavy rainfall, primarily attributed to the impact of the highly severe cyclonic storm Biparjoy. This cyclone, along with others, significantly affected the fishing community along the coastal areas of Gujarat, as IndiaSpend reported in June 2023.

In July, regions such as Konkan and Goa, coastal Karnataka, Uttarakhand, Himachal Pradesh and Telangana encountered intense rainfall events, largely influenced by the presence of low-pressure systems. During this month, 420 persons were reported dead, more than 95 were injured, over 55 persons were reported missing and more than 40 livestock perished due to extreme weather events.


August saw a concentration of extremely heavy rainfall events in Odisha and Gangetic West Bengal, driven by the formation of a deep depression and a low-pressure area in the Bay of Bengal. Additionally, two western disturbances triggered substantial rainfall and floods in Himachal Pradesh and Uttarakhand. As September unfolded, the focus shifted to Madhya Pradesh, Bihar, and western Uttar Pradesh, where extremely heavy rainfall events were observed due to the formation of low-pressure areas in the Bay of Bengal.


Besides Mocha and Biparjoy, India saw other cyclonic events this year, including one ‘extremely severe cyclonic storm’, Tej, which formed over the Arabian Sea during October 20-25. A ‘very severe cyclonic storm’, Hamoon, also formed over the Bay of Bengal during October 21-25.

In early December, Cyclonic Storm Michaung brought substantial rainfall across various regions. Heavy to very heavy rainfall occurred in several places, with particularly extreme rainfall reported in the northern parts of coastal Tamil Nadu, Rayalaseema and south-coastal Andhra Pradesh. On December 18, exceptionally heavy rainfall was observed over Thoothukudi (Kayalpattinam - 95 cm) and Tirunelveli (Moolaikaraipatti - 62 cm) districts of south Tamil Nadu.

The nationwide impact of Michaung was pronounced, with the country experiencing three times the usual amount of rainfall during the first week of December. In central India, the surge in rainfall was even more dramatic, reaching up to five times the typical levels.


Heat wave conditions in June

As we said above, unseasonably cool temperatures prevailed across the country for a significant portion of May 2023. This cooling trend was primarily attributed to active thunderstorm activity and the frequent passage of western disturbances over northern India, coupled with the influence of other supporting synoptic-scale weather systems over central and Peninsular India.


In contrast, eastern India saw more heat wave days in June compared to the norm. Particularly affected were areas in West Bengal, Odisha, Bihar, eastern Uttar Pradesh, Jharkhand, Chhattisgarh, coastal Andhra Pradesh, and Telangana, where the count ranged from 11 to 19 days of extreme heat as opposed to the usual two to four days. Additionally, adjoining central parts of India, covering eastern Madhya Pradesh and Maharashtra’s Vidarbha, observed seven to nine heat wave days.


The severity of the heat wave varied, with Bihar experiencing heat wave to severe heat wave conditions on almost all dates from June 1-22, while West Bengal encountered such conditions from June 1-18, and eastern Uttar Pradesh from June 12-21.

The Centre for Science and Environment in its report “Climate India 2023: An assessment of extreme weather events” pointed out that the country experienced extreme weather events on an almost daily basis in the first nine months of the year. The report was released on November 29, and does not account for Cyclone Michuang, which ravaged parts of the country in early December.

The report said Madhya Pradesh witnessed the highest number of extreme weather events (138), while the largest number of deaths occurred in Bihar (642).

The CSE report estimates that 2,923 people died, 1.84 million hectares of crops were affected by September, 80,000 homes were destroyed, and over 92,000 animals were killed in various weather events across the year. The report warned that the final numbers could be even higher as all data for the year had not been collected at the time of creating the report.

CSE director general Sunita Narain was quoted in the media as saying that what the country witnessed in 2023 is “the new abnormal”.

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