An analysis of the daily district wise rainfall data from India Meteorological Department (IMD) for the month of Aug 2021, 3rd month of India’s South West Monsoon 2021 shows that there were 431 instances when district rainfall of a day was above 50 mm. The normal monthly rainfall of India Aug is 258.2 mm and actual rainfall was a huge 24.13% below normal at 195.9 mm[i], the actual average daily rainfall in this month was about 6.45 mm. Such high rainfall instances included 371 instances when rainfall was 50-100 mm, 48 instances when it was 100-150 mm, 11 times it was 150-200 mm and just once above 200 mm. Interestingly, in June 2021[ii] and July 2021[iii] there were seven instances when rainfall was above 200 mm, when the rainfall is supposed to be much below July rainfall. As noted in detailed article[iv], the July 2021 rainfall all over India was 6.7% below normal.
The lone instance in Aug 2021 when rainfall in a district crossed 200 mm was in Shivpuri district of West Madhya Pradesh, where on Aug 3, the rainfall was unbelievable 312.8 mm.
Out of 694 districts of India, 216 districts or about 31.3 of the districts experienced such high rainfall in August 2021, many districts that had more than one such high rainfall days. The highest number of such instances were seen (in June and July 2021 Konkan had the highest number of such instances, 48 & 56 respectively) in Meghalaya, where for the seven districts there were 41 instances when rainfall was above 50 mm. Arunachal Pradesh was close second with 39 instances involving 7 of Arunachal’s’s 16 districts. Incidentally, Assam had 46 such instances in June 2021 and 31 in July 2021 and now only 26 in August 2021.
Among the five regions of India (North, South, East, West and North East), North East India had the highest number of such instances (135), followed by East India (121) and West India (104). North India had the least such instances at 22.
North East India In the table below are given the number of such high rainfall district days in each of the states in North East India in each of the rainfall categories in August 2021.
| State | Districts that had over 50 mm rainfall at least on one day in Aug 2021 (Total no of districts) | No of district days when rainfall 50-100 mm | No of district days when Rainfall 100-150 mm | No of district days when Rainfall 150-200 | No of district days when Rainfall over 200 mm | Total no of district days when rainfall over 50 mm |
| Arunachal Pradesh | 7 (16) | 34 | 4 | 1 | 0 | 39 |
| Assam | 13 (27) | 26 | 0 | 0 | 0 | 26 |
| Meghalaya | 6 (7) | 24 | 12 | 5 | 0 | 41 |
| Nagaland | 3 (11) | 3 | 1 | 0 | 0 | 4 |
| Manipur | 4 (9) | 7 | 2 | 0 | 0 | 9 |
| Mizoram | 5 (8) | 8 | 1 | 0 | 0 | 9 |
| Tripura | 4 (4) | 4 | 0 | 0 | 0 | 4 |
| Sikkim | 2 (4) | 3 | 0 | 0 | 0 | 3 |
| North East India | 44 (86) | 109 | 20 | 6 | 0 | 135 |
East India
| State | Districts that had over 50 mm rainfall at least on one day in Aug 2021 (Total no of districts) | No of district days when rainfall 50-100 mm | No of district days when Rainfall 100-150 mm | No of district days when Rainfall 150-200 | No of district days when Rainfall over 200 mm | Total no of district days when rainfall over 50 mm |
| W Bengal | 12 (19) | 27 | 2 | 0 | 0 | 29 |
| Odisha | 2 (30) | 3 | 0 | 0 | 0 | 3 |
| Jharkhand | 8 (24) | 8 | 2 | 0 | 0 | 10 |
| Bihar | 16 (38) | 25 | 1 | 0 | 0 | 26 |
| Uttar Pradesh | 39 (74) | 47 | 6 | 0 | 0 | 53 |
| East India | 79 (185) | 110 | 11 | 0 | 0 | 121 |
North India
| State/ Union Territory | Districts that had over 50 mm rainfall at least on one day in Aug 2021 (Total no of districts) | No of district days when rainfall 50-100 mm | No of district days when Rainfall 100-150 mm | No of district days when Rainfall 150-200 | No of district days when Rainfall over 200 mm | Total no of district days when rainfall over 50 mm |
| Uttarakhand | 4 (13) | 8 | 0 | 1 | 0 | 9 |
| Haryana | 2 (22) | 2 | 0 | 0 | 0 | 2 |
| Chandigarh | 0 (1) | 0 | 0 | 0 | 0 | 0 |
| Delhi | 6 (9) | 5 | 2 | 0 | 0 | 7 |
| Punjab | 0 (22) | 0 | 0 | 0 | 0 | 0 |
| Himachal Pradesh | 2 (12) | 2 | 0 | 0 | 0 | 2 |
| Jammu & Kashmir | 2 (20) | 2 | 0 | 0 | 0 | 2 |
| Ladakh | 0 (2) | 0 | 0 | 0 | 0 | 0 |
| North India | 16 (101) | 19 | 2 | 1 | 0 | 22 |
West India
| State | Districts that had over 50 mm rainfall at least on one day in Aug 2021 (Total no of districts) | No of district days when rainfall 50-100 mm | No of district days when Rainfall 100-150 mm | No of district days when Rainfall 150-200 | No of district days when Rainfall over 200 mm | Total no of district days when rainfall over 50 mm |
| Rajasthan | 14 (33) | 29 | 6 | 0 | 0 | 35 |
| Madhya Pradesh | 22 (51) | 28 | 8 | 2 | 1 | 39 |
| Diu Daman | 1 (2) | 1 | 1 | 2 | 0 | 4 |
| Gujarat | 4 (34) | 7 | 0 | 0 | 0 | 7 |
| Dadra Nagarhaveli | 1 (1) | 2 | 0 | 0 | 0 | 2 |
| Goa | 0 (2) | 0 | 0 | 0 | 0 | 0 |
| Maharashtra | 9 (36) | 10 | 0 | 0 | 0 | 10 |
| Chhattisgarh | 5 (27) | 7 | 0 | 0 | 0 | 7 |
| West India | 56 (186) | 84 | 15 | 4 | 1 | 104 |
South India
| State | Districts that had over 50 mm rainfall at least on one day in Aug 2021 (Total no of districts) | No of district days when rainfall 50-100 mm | No of district days when Rainfall 100-150 mm | No of district days when Rainfall 150-200 | No of district days when Rainfall over 200 mm | Total no of district days when rainfall over 50 mm |
| Andhra Pradesh | 0 (13) | 0 | 0 | 0 | 0 | 0 |
| Telangana | 8 (33) | 9 | 0 | 0 | 0 | 9 |
| Tamil Nadu | 1 (38) | 1 | 0 | 0 | 0 | 1 |
| Puducherry | 3 (4) | 5 | 0 | 0 | 0 | 5 |
| Karnataka | 6 (30) | 8 | 0 | 0 | 0 | 8 |
| Kerala | 8 (14) | 18 | 0 | 0 | 0 | 18 |
| Lakshadweep | 1 (1) | 1 | 0 | 0 | 0 | 1 |
| Andaman & Nicobar | 2 (3) | 7 | 0 | 0 | 0 | 7 |
| South India | 29 (136) | 49 | 0 | 0 | 0 | 49 |
Date wise High Rainfall Events In the table below we have given total daily high rainfall events in the same categories as above (50-100 mm, 100-150 mm, 150-200 mm, 200+ mm) in districts of India in August 2021.
| Date in Aug 2021 | No of district days when rainfall 50-100 mm | No of district days when rainfall 100-150 mm | No of district days when rainfall 150-200 mm | No of district days when rainfall over 200 mm | Total No of district days when rainfall over 50 mm |
| 1 | 22 | 3 | 0 | 0 | 25 |
| 2 | 19 | 6 | 0 | 0 | 25 |
| 3 | 6 | 5 | 2 | 1 | 14 |
| 4 | 12 | 3 | 0 | 0 | 15 |
| 5 | 11 | 0 | 0 | 0 | 11 |
| 6 | 9 | 1 | 0 | 0 | 10 |
| 7 | 13 | 3 | 0 | 0 | 16 |
| 8 | 8 | 2 | 0 | 0 | 10 |
| 9 | 7 | 0 | 0 | 0 | 7 |
| 10 | 15 | 2 | 0 | 0 | 17 |
| 11 | 10 | 3 | 0 | 0 | 13 |
| 12 | 14 | 3 | 1 | 0 | 18 |
| 13 | 22 | 2 | 1 | 0 | 25 |
| 14 | 10 | 2 | 1 | 0 | 13 |
| 15 | 10 | 0 | 0 | 0 | 10 |
| 16 | 4 | 0 | 0 | 0 | 4 |
| 17 | 6 | 0 | 0 | 0 | 6 |
| 18 | 9 | 1 | 0 | 0 | 10 |
| 19 | 12 | 0 | 1 | 0 | 13 |
| 20 | 20 | 1 | 0 | 0 | 21 |
| 21 | 16 | 2 | 1 | 0 | 19 |
| 22 | 9 | 0 | 0 | 0 | 9 |
| 23 | 12 | 1 | 1 | 0 | 14 |
| 24 | 3 | 1 | 0 | 0 | 4 |
| 25 | 9 | 1 | 0 | 0 | 10 |
| 26 | 16 | 3 | 2 | 0 | 21 |
| 27 | 22 | 1 | 0 | 0 | 23 |
| 28 | 14 | 1 | 0 | 0 | 15 |
| 29 | 14 | 1 | 0 | 0 | 15 |
| 30 | 12 | 0 | 0 | 0 | 12 |
| 31 | 5 | 0 | 1 | 0 | 6 |
| TOTAL IN AUG 2021 | 371 | 48 | 11 | 1 | 431 |
INDIA
| Region | Districts that had over 50 mm rainfall at least on one day in June 2021 (Total no of districts) | No of district days when rainfall 50-100 mm | No of district days when Rainfall 100-150 mm | No of district days when Rainfall 150-200 | No of district days when Rainfall over 200 mm | Total no of district days when rainfall over 50 mm |
| North East | 44 (86) | 109 | 20 | 6 | 0 | 135 |
| East | 71 (185) | 110 | 11 | 0 | 0 | 121 |
| North | 16 (101) | 19 | 2 | 1 | 0 | 22 |
| West | 56 (186) | 84 | 15 | 4 | 1 | 104 |
| South | 29 (136) | 49 | 0 | 0 | 0 | 49 |
| INDIA | 216 (694) | 371 | 48 | 11 | 1 | 431 |
SANDRP (ht.sandrp@gmail.com)
END NOTES:
[i] https://sandrp.in/2021/09/01/june-aug-2021-district-wise-rainfall-in-indias-sw-monsoon/
[ii] https://sandrp.in/2021/07/23/high-rainfall-days-in-indias-districts-in-june-2021/
[iii] https://sandrp.in/2021/08/06/july-2021-high-rainfall-days-in-indias-districts/
[iv] https://sandrp.in/2021/07/31/june-july-2021-district-wise-sw-monsoon-rainfall-in-india/
SANDRP 