June Aug 2022: District wise rainfall in India’s SW Monsoon

In the just concluded month of Aug 2022, the third month of India’s South West 2022 monsoon, India received 263.8 mm rainfall, 3.5% above the normal Aug rainfall of 254.9 mm as per India Meteorological department (IMD). In Aug 2021, the rainfall was 195.9 mm [i], about 24.13% below normal and in Aug 2020, the rainfall was 327 mm [ii], or about 26.6% above normal.

However, the distribution of rainfall has been far from normal in July 2022. June 2022 had ended with 8% deficit in rainfall [iii] while July 2022 had ended with 16.8% surplus rainfall [iv]. June 2022 also had very large number of high rainfall days.

The rainfall in first 4 days and last 7 days of Aug 2022 as also on Aug 6, Aug 13 and during Aug 17-19 was below normal at all India level as can be seen from the bar chart below from IMD. The rainfall in remaining 14 days was above normal. The Highest one day rainfall at all India level in Aug 2022 was 17.6 mm (110% above normal) on Aug 15, India’s independence day. This is the highest one day rainfall in SW Monsoon 2022 so far. There were nine days in Aug 2022 when day rainfall at all India level was above 10 mm. There were five days in the month when the day rainfall was below 5 mm, with the lowest rainfall of 3.5 mm recorded on the last day of the month.

Region wise rainfall graphs The IMD divides the country into four regions. As can be seen from the following graph, the East and North East India had 19% below normal for June-Aug 2022, the three months of SW Monsoon this year so far.

The North West India ended the three months period of June Aug 2022 with just 1% deficit.

The Central India ended the June Aug 2022 period with 18% surplus rainfall.

The South Peninsular India had the highest surplus rainfall at 28% at the end of June Aug 2022 period.

State wise rainfall As can be seen from IMD rainfall map for June-Aug 2022, only Tamil Nadu (87% above normal rainfall) had large excess rainfall of above 60% surplus in this period. Eight states had Excess (rainfall 20-59% above normal) in this three month period. 21 states had normal rainfall with rainfall between 19% deficit and 19% surplus, while six states (UP, Bihar, Jharkhand, Delhi, Tripura, Manipur) had deficit rainfall with rainfall 20-59% below normal in this three months.

Sub-Division wise rainfall IMD rainfall map for sub-division wise rainfall, out of IMD’s 36 subdivisions, three (Tamil Nadu-Puducherry-Karaikal-highest surplus of 87%, South Interior Karnataka and Western Rajasthan) had large surplus rainfall during June Aug 2022. 11 sub divisions, mostly in south and Western India had surplus rain, 16 sub divisions had normal rain, while six sub divisions had Deficit rainfall. The Highest deficit was 44% for East and West Uttar Pradesh.

River Basin wise rainfall IMD also provides river basin wise rainfall map. As can be seen from the map, IMD has no data for two basins: Jhelum and Upper Indus). IMD also strangely reports no rainfall in Vaippar-Pamba interstate basin between Kerala and Tamil Nadu. This is clearly an impossibility. It is this kind of anomalies that raise questions about accuracy of IMD’s river basin wise rainfall figures. It may be added here that there are fewer anomalies this year than what we saw in last couple of years.