Mumbai remained under an India Meteorological Department (IMD) yellow heatwave warning for the third consecutive day on Wednesday, with temperatures at key observatories staying more than 3°C above normal and hot, humid conditions expected to continue through October 16.
The IMD Santacruz observatory recorded a maximum temperature of 37.8°C, which was 4.1°C above normal. At Colaba, the maximum reached 36.4°C, or 3.2°C above normal. The weather bureau has issued a heatwave warning for October 15 and forecast hot and humid conditions for October 16.
The prolonged spell has pushed Mumbai’s October temperatures to unusual levels. The city recorded 38°C a day earlier, making it the second-hottest October day in 11 years, according to the report. The mercury touched 38.2°C on Monday, the highest October maximum recorded in the city during the same period.
The IMD has forecast light to moderate rain and thundershowers for Mumbai and Thane on October 17 and 18. The expected rainfall could bring temporary relief, although current conditions are likely to remain uncomfortable until then.
An IMD official said the heatwave was linked to an anticyclone that had shifted slightly northwards, along with an easterly wave influencing the region. The official said temperatures could again reach 37.8°C on Thursday, potentially resulting in seven consecutive days above 37°C.
“While the city does experience spells of two to three days of high temperatures, a continuous stretch of six to seven days is not normal,” the IMD official said. The official added that the role of the easterly wave in prolonging the hot spell required examination, particularly in the context of a strong El Niño year.
The IMD describes an easterly wave as a weather system with a trough travelling from east to west. Such a system can interact with weather systems approaching from the west and trigger intense thunderstorms.
Akshay Sunil, vice-president of WeatherEx Pvt Ltd, said the heat over Mumbai was part of a broader warm spell across western India. According to him, a high-pressure circulation and easterly to northeasterly winds were limiting the usual cooling sea breeze, while clear post-monsoon skies were allowing strong daytime heating. Humidity was adding to the discomfort, he said.
WeatherEx’s extended outlook suggested that above-normal temperatures could continue through at least October 22. Localised light showers could provide temporary relief in parts of the Konkan region after October 22, Sunil said.
For residents, the warning means continued exposure to high daytime heat and humidity across the city, with relief dependent on the expected rain and a shift in the weather systems influencing the region. The IMD’s next forecast updates will determine whether the warning is extended beyond October 15 and how rainfall develops over Mumbai and Thane on October 17 and 18.
