An analysis of the daily district wise rainfall data from India Meteorological Department (IMD) for the month of September 2023, the last month of India’s South West Monsoon 2023 shows that there were 406 (417 in Sept 2022[i] and 489 in Sept 2021[ii]) instances when district rainfall of a day was above 50 mm. Such high rainfall instances included 330 (365 and 374 in Sept 2022 and 2021 respectively) instances when rainfall was 50-100 mm, 64 (47 and 84 in Sept 2022 and 2021) instances when it was 100-150 mm, 10 (3 and 20 in Sept 2022 and 2021) times when it was 150-200 mm and twice (two and eleven in Sept 2022 and 2021 respectively) when rainfall in a day was above 200 mm.
Out of 717 districts of India, 251 districts experienced such high rainfall in Sept 2023, many districts had more than one such high rainfall days. The highest number of such instances were seen in Madhya Pradesh, where for the 52 districts (only 29 of them saw such instances) there were 50 instances when rainfall was above 50 mm. Chhattisgarh and Gujarat were second with 28 such instances each.
Among the five regions of India (North, South, East, West and North East), West India had the highest number of such instances (143), followed by East India (112) and South India (77). North India had the least such instances in Sept 2023 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 Sept 2023.
| State | No of Districts that had over 50 mm rainfall at least on one day in Sep 2023 (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 | 5 (16) | 6 | 0 | 0 | 0 | 6 |
| Assam | 11 (27) | 17 | 0 | 0 | 0 | 17 |
| Meghalaya | 4 (11) | 5 | 1 | 0 | 0 | 6 |
| Nagaland | 3 (11) | 3 | 3 | 0 | 0 | 6 |
| Manipur | 2 (9) | 2 | 1 | 0 | 0 | 3 |
| Mizoram | 5 (8) | 9 | 0 | 0 | 0 | 9 |
| Tripura | 3 (8) | 4 | 0 | 0 | 0 | 4 |
| Sikkim | 1 (4) | 1 | 0 | 0 | 0 | 1 |
| North East India | 34 (94) | 47 | 5 | 0 | 0 | 52 |
East India
| State | No of Districts that had over 50 mm rainfall at least on one day in Sep 2023 (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 | 9 (19) | 16 | 2 | 1 | 0 | 19 |
| Odisha | 18 (30) | 25 | 1 | 0 | 0 | 26 |
| Jharkhand | 10 (24) | 15 | 1 | 0 | 0 | 16 |
| Bihar | 19 (38) | 15 | 10 | 1 | 0 | 26 |
| Uttar Pradesh | 18 (75) | 17 | 7 | 1 | 0 | 25 |
| East India | 74 (186) | 88 | 21 | 3 | 0 | 112 |
North India
| State/ Union Territory | No of Districts that had over 50 mm rainfall at least on one day in Sep 2023 (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 | 5 (13) | 9 | 0 | 0 | 0 | 9 |
| Haryana | 1 (22) | 1 | 0 | 0 | 0 | 1 |
| Chandigarh | 0 (1) | 0 | 0 | 0 | 0 | 0 |
| Delhi | 2 (9) | 2 | 0 | 0 | 0 | 2 |
| Punjab | 1 (22) | 1 | 0 | 0 | 0 | 1 |
| Himachal Pradesh | 2 (12) | 2 | 0 | 0 | 0 | 2 |
| Jammu & Kashmir | 4 (20) | 6 | 1 | 0 | 0 | 7 |
| Ladakh | 0 (2) | 0 | 0 | 0 | 0 | 0 |
| North India | 15 (101) | 21 | 1 | 0 | 0 | 22 |
West India
| State | No of Districts that had over 50 mm rainfall at least on one day in Sep 2023 (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 | 7 (33) | 8 | 2 | 1 | 0 | 11 |
| Madhya Pradesh | 29 (52) | 31 | 14 | 3 | 2 | 50 |
| Diu Daman | 1 (2) | 1 | 0 | 0 | 0 | 1 |
| Gujarat | 18 (33) | 18 | 8 | 2 | 0 | 28 |
| Dadra Nagarhaveli | 1 (1) | 1 | 1 | 0 | 0 | 2 |
| Goa | 2 (2) | 4 | 1 | 0 | 0 | 5 |
| Maharashtra | 10 (36) | 15 | 3 | 0 | 0 | 18 |
| Chhattisgarh | 15 (27) | 27 | 1 | 0 | 0 | 28 |
| West India | 83 (186) | 105 | 30 | 6 | 2 | 143 |
South India
| State | No of Districts that had over 50 mm rainfall at least on one day in Sep 2023 (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 | 8 (26) | 9 | 0 | 0 | 0 | 9 |
| Telangana | 18 (33) | 22 | 0 | 0 | 0 | 22 |
| Tamil Nadu | 4 (38) | 4 | 0 | 0 | 0 | 4 |
| Puducherry | 1 (4) | 2 | 1 | 0 | 0 | 3 |
| Karnataka | 2 (31) | 2 | 0 | 0 | 0 | 2 |
| Kerala | 9 (14) | 15 | 1 | 0 | 0 | 16 |
| Lakshadweep | 0 (1) | 0 | 0 | 0 | 0 | 0 |
| Andaman & Nicobar | 3 (3) | 15 | 5 | 1 | 0 | 21 |
| South India | 45 (150) | 69 | 7 | 1 | 0 | 77 |
INDIA
| Region | No of Districts that had over 50 mm rainfall at least on one day in Sept 2023 (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 | 34 (94) | 47 | 5 | 0 | 0 | 52 |
| East | 74 (186) | 88 | 21 | 3 | 0 | 11 |
| North | 15 (101) | 21 | 1 | 0 | 0 | 22 |
| West | 83 (186) | 105 | 30 | 6 | 2 | 143 |
| South | 45 (150) | 69 | 7 | 1 | 0 | 77 |
| INDIA | 251 (717) | 330 (365) | 64 (47) | 10 (3) | 2 (2) | 406 (417) |
Note: The figures in the bracket in the last two for columns 3-7 are for previous year. Figures in the bracket in second row are the number of total districts in specific state or region in all the tables.
One can see in above table that while the total no of high rainfall district days during Sept 2023 were 406, lower than 417 in Sept 2022, the number of district days when rainfall is in higher ranges (100-150 mm and 150-200 mm) in a day are higher in Sept 2023 compared to Sept those in Sept 2022. This is one of the indications showing that frequency of high intensity rainfall is going up.
SANDRP (ht.sandrp@gmail.com)
[i] https://sandrp.in/2022/10/02/high-rainfall-days-in-indias-districts-in-sept-2022/
[ii] https://sandrp.in/2021/10/07/high-rainfall-days-in-indias-districts-in-sept-2021/
SANDRP 