Climate report: Warming trend persists in Kerala despite slight relief in 2025

Kerala experienced its 13th warmest year on record in 2025, with the annual mean land surface air temperature reaching 25.82°C, about 0.22°C above the Long Period Average (LPA, 1991–2020).

According to the Statement on Climate for the State of Kerala: 2025, released by the Institute for Climate Change Studies under the Kerala State Council for Science, Technology and Environment, temperatures remained higher than normal, though the year was significantly cooler than 2024 – the warmest year on record for the State since observations began in 1901. In 2024, the annual mean temperature was 0.99°C above normal.

Unlike 2024, which witnessed persistent record-breaking heat, 2025 was characterised by mixed seasonal temperature patterns. The winter season was notably warmer than average, with a temperature anomaly of +0.63°C, ranking as the fifth warmest winter on record. Other seasons remained close to their respective LPAs. The State’s annual mean maximum and minimum temperatures were above normal by 0.13°C and 0.31°C, ranking as the 14th and 10th warmest, respectively, since 1901.

The broader trend points to persistent warming. The report notes that eight of the 10 warmest years on record have occurred during the recent decade (2016–2025), making it the warmest decade on record. The annual mean temperature during 2011–2020 was 0.35°C above normal, increasing further to 0.56°C during 2016–2025. Over the period from 1901 to 2025, Kerala’s annual mean temperature has risen at a rate of about 1.15°C per 100 years.

Further analysis shows that maximum temperatures have been rising faster than minimum temperatures in the State. Between 1901 and 2025, average maximum temperature increased by 1.77°C per 100 years, compared with a relatively smaller rise of 0.53°C in average minimum temperature. Until the late 1980s, annual maximum temperatures were generally lower than minimum temperatures. Thereafter, the trend “reversed”, with maximum temperatures rising faster than minimum temperatures, leading to higher annual average diurnal temperature variation in recent decades.

While the State received 2,925.7 mm of rainfall in 2025-about 1.2% above the long-period average (1971–2020), the report notes that both monsoon seasons recorded deficits. Southwest monsoon rainfall was 13% below normal, while the northeast monsoon saw a sharper shortfall of 21%, continuing a long-term declining trend observed over the past century.

The State’s coastal waters also remained “persistently warm” for most of the year. The annual mean sea surface temperature was 0.47°C above normal in the north and 0.42°C in the south. Although cooler than the record warmth of 2024, the long-term trend indicates “sustained ocean warming”.