Climate data on maximum and minimum temperature, relative humidity, air velocity and rainfall were collected from the concern District Collectorate and Agro Climate Research Centre, TNAU, Coimbatore for three districts (Tiruchirapalli, Thanjavur, and Pudukkottai) in the Cauvery delta region of Tamil Nadu, India, over a 10-year period (2009-2018). The average monthly maximum temperature (°C) was highest in May (38.30 ± 0.34 to 38.70 ± 0.40), and lowest in December (29.20 ± 0.20 to 30.00 ± 0.33). The average monthly minimum temperature (°C) was higher in May (28.30 ± 0.21 to 29.30 ± 0.21) but declined in January (19.70 ± 0.26 to 20.70 ± 0.15). The average monthly humidity (%) was high in November (78.30 ± 1.80 to 79.50 ± 1.65) and low in June and July (49.20 ± 1.63 to 50.60 ± 1.19). The average monthly air velocity (m/s) was more in June and July, ranging from 4.27 ± 0.20 to 4.69 ± 0.17, and least in October, ranging from 2.52 ± 0.12 to 2.79 ± 0.15. The average monthly rainfall (mm) was high in November (149.68 ± 36.44 to 225.20 ± 44.83) and low in February (3.41 ± 1.84 to 5.21 ± 2.33). During 2009-2018, the Mann-Kendall trend test revealed a significant (P<0.01) increasing positive trend for maximum and minimum temperatures and a non-significant decreasing negative trend for relative humidity, with the exception of Thanjavur district, where there was a significant (P<0.01) decrease in relative humidity. Similarly, the Mann-Kendall trend test indicated a non-significant increasing positive trend of air velocity but no trend in rainfall during the last decade (2009 to 2018) in Cauvery delta region of Tamil Nadu.