Bengaluru recorded a temperature of 33.6 °C in July 2024, marking the hottest July day for the city in 112 years [1], [2].

This temperature spike signals a significant disruption in regional weather patterns, as the southwest monsoon typically provides cooling rains during this period. The failure of these rains has created drought-like conditions across South India, threatening agriculture and water security.

The previous July record for Bengaluru was 33.3 °C, a mark set in 1914 and again in 1926 [1]. The recent jump to 33.6 °C [1] represents a century-scale anomaly for the city. Across the state of Karnataka, temperature anomalies have ranged from three °C to five °C above normal [3].

The heatwave extended beyond Karnataka, affecting Tamil Nadu and Kerala. In Madurai, temperatures reached 42.5 °C [4], while Chennai saw temperatures climb to nearly 40 °C [4]. These extreme highs are attributed to a weakened southwest monsoon that reduced critical rainfall [3], [4].

In Kerala, the impact of the failing monsoon is evident in the rainfall data. The region has seen a rainfall deficit of over 30 % [4]. This lack of precipitation has prevented the natural cooling process that usually accompanies the season, leaving the region vulnerable to sustained high temperatures.

Meteorologists said that the reduced monsoon activity allowed temperatures to rise significantly above historical averages. The combination of low humidity and high solar radiation, typical of a failing monsoon, has intensified the heat across the southern peninsula [3], [4].

“Bengaluru recorded a temperature of 33.6 °C in July 2024, marking the hottest July day for the city in 112 years”

The breach of a 112-year-old temperature record suggests that traditional monsoon patterns in South India are becoming increasingly volatile. When the southwest monsoon weakens, the region loses its primary mechanism for temperature regulation, leading to compound crises where extreme heat and water scarcity occur simultaneously. This trend increases the risk of crop failure and urban heat stress in densely populated hubs like Bengaluru and Chennai.