Mumbai’s heatwave conditions intensified on Friday, with the Santacruz observatory recording 37.8°C, or 4.7°C above normal, as the India Meteorological Department retained its yellow alert for Mumbai and Thane and warned of hot and humid conditions in isolated areas on Saturday.
Santacruz, the benchmark weather station for Mumbai, recorded a maximum temperature slightly higher than Thursday’s 37.6°C. The reading was among the city’s highest October temperatures in recent years and marked the second consecutive day of intense heat. The observatory has recorded three of the 10 highest October temperatures since record-keeping began in 1951 during the past week: 37.4°C on October 3, 37.6°C on October 8 and 37.8°C on October 9.
The IMD attributed the spike to an anticyclone over Mumbai and neighbouring areas. The circulation pattern causes air to sink towards the ground, while clear and cloudless skies have further increased daytime temperatures. IMD scientist Sushma Nair said the system was well organised but was expected to become less organised and shift slightly on Saturday, potentially bringing some relief.
Mumbai’s Colaba observatory recorded a maximum of 37°C on Friday, which was 4.4°C above normal. The reading was among Colaba’s highest October temperatures since 2014. The station’s highest temperature during that period was 37.2°C on October 30, 2018, while Santacruz’s October high since 2014 remains 38.6°C, recorded on October 17, 2015.
Humidity added to the discomfort. Relative humidity at Colaba was recorded at 81%, while Santacruz recorded 73%. The combination of above-normal temperatures and high humidity can increase heat stress for people working outdoors, commuting across the city or living in buildings with limited ventilation, although the supplied IMD advisory does not specify any separate public-health restrictions.
The weather pattern has also affected the sea breeze that normally moderates daytime temperatures along Mumbai’s coast. Easterly and northerly winds, described as relatively dry, and prevailing northeasterly and easterly winds over Maharashtra have delayed the development of the sea breeze. Several locations across the Konkan region recorded temperatures between 38°C and 39°C.
The monsoon withdrew from Mumbai on October 3, earlier than the usual withdrawal date of October 8. September was largely dry, with limited thunderstorm activity during a period when such storms are generally observed as the monsoon withdraws. These conditions have left the city experiencing unusually hot weather soon after the end of the rainy season.
For Mumbai and other coastal areas, the IMD’s heatwave criteria consider both the absolute maximum temperature and its departure from normal. A heatwave is declared when the maximum temperature reaches at least 37°C and remains 4.5°C or more above normal for two consecutive days. The IMD has retained its yellow alert for Mumbai and Thane and issued a warning for hot and humid conditions at isolated places on Saturday.
