COIMBATORE: Tamil Nadu is likely to receive normal rainfall during the upcoming Northeast Monsoon (NEM) season from October to December 2026, with the state expected to receive around 438 mm of rainfall against the normal 434 mm, according to a district-level seasonal rainfall forecast prepared by Tamil Nadu Agricultural University (TNAU) on Friday.
The forecast, prepared at a 60 per cent probability level, used the Southern Oscillation Index (SOI) and Sea Surface Temperature (SST) values of the Pacific and Indian Oceans recorded during July and August.
According to TNAU, the state received 254 mm of rainfall during the Southwest Monsoon (June-September) against the normal 292 mm, registering a 13% deficit as on September 22. The upcoming NEM is expected to provide partial relief by improving soil moisture, reservoir storage and groundwater recharge.
The forecast noted that prevailing El Niño conditions could influence monsoon circulation and result in uneven rainfall distribution across the state. Coastal districts could experience intense wet spells associated with cyclonic systems, while interior districts may witness relatively longer dry spells, particularly during December.
Among the districts, Mayiladuthurai is expected to record the highest rainfall during the NEM, with 991 mm against its normal of 910 mm, an increase of 9%. Chengalpattu is expected to receive 780 mm against 720 mm, while Nagapattinam is likely to receive 864 mm against 849 mm.
In Coimbatore, the rainfall is expected to remain almost normal at 367 mm against the normal 366 mm. Nilgiris is expected to receive 444 mm against 451 mm, registering a 2% deficit. Tiruppur is forecast to receive 306 mm against the normal 328 mm, a 7% deficit, while Erode may receive 304 mm against 314 mm.
TNAU advised farmers to closely follow weather forecasts and agro-advisories while making decisions on sowing, irrigation and fertiliser application. Farmers have also been advised to harvest and store excess rainwater in farm ponds during wet spells for use during dry periods.
The university recommended mulching, random tie-ridging and conservation furrows to conserve soil moisture in rain-fed areas. In rice fields, farmers may adopt Alternate Wetting and Drying (AWD), wherever feasible, to improve water-use efficiency.
