Long‐Term Trends of Heat Stress Over the Coastal Regions of India

ABSTRACT This study investigates long‐term changes in wet bulb temperature (WBT) along the Indian coasts during 1981–2020, together with associated variations in dry bulb temperature (DBT) and specific humidity ( q ). The analysis is carried out separately for the four seasons—January–March (JFM), April–June (AMJ), July–September, and October–December (OND). The results show a significant rise in the seasonal daily maximum WBT across all seasons, with the most pronounced increase along the East Coast (EC), particularly during the AMJ season. On the West Coast (WC), WBT trends are primarily driven by DBT, whereas on the EC, both DBT and humidity contribute strongly to the observed WBT changes. Probability density function analysis indicates a persistent warming and moistening tendency across the coastal regions. Extremes of WBT, DBT, and relative humidity have intensified, with a marked escalation after 2000. The findings highlight global warming as the dominant driver of WBT changes. Notably, the percentage increase in q per 1°C warming is greater along the EC (up to 8.3%) than the WC (up to 6.5%), especially during the cooler seasons (JFM and OND). These results highlight that continued warming will likely intensify coastal heat stress across seasons, posing growing risks to communities along India's coasts.