Annual mean surface air temperature averaged over Kerala during 1901-2021 show a significant increasing trend of 1.050C/100 years in line with the significant increasing trends observed over most parts of the country. During the same period, the State averaged maximum temperature showed a significant increasing trend (1.670C/100 years) and the State averaged minimum temperature a relatively lower increasing trend (0.420C/100 years).
The Kerala State averaged annual mean land surface air temperature during 2021 was +0.400C warmer than average (1971-2020) making 2021, the eighth warmest year for Kerala on record since 1901. The warmest year for Kerala on record prior to 2021 was 2016 (+0.970C) followed by 2019 (+0.880C). The warmer than normal annual mean temperature was mainly contributed by the above average mean temperature during the southwest monsoon season (0.730C). The 8 of the 10 warmest years in record were pertaining to the recent decade (2012-2021) and therefore the annual mean temperature of Kerala during the past decade (2011- 2020/ 2012-2021) was also the warmest decade on record with the decadal averaged annual mean temperature anomaly of 0.510C /0.550C. The annual maximum and minimum temperatures averaged over the state during the year 2021 were also warmer than average with anomalies of 0.390C (9th warmest) & 0.420C (6th warmest).
Significant increasing trends in the district averaged maximum and mean temperatures have been observed over all the 14 districts of the State. However, in the case of minimum temperature, significant increasing trends were observed in 9 out of the 14 districts. Among the remaining five districts, Kannur and Pathanamthitta showed increasing but non- significant trends, Kasaragod, the northern most district showed significant decreasing trend and Kollam and Thiruvananthapuram, the two southern most districts showed decreasing but insignificant trends.