Mumbai: Notorious October heat to persist well into November

The IMD, on Sunday, recorded 36.4°C at its Santacruz observatory. Representational pic/Sameer Markande

Winter is coming in Mumbai, but not anytime soon. While the hot weather is expected to persist till October 31, the actual onset of winter in the city is not expected anytime before Diwali, indicated meteorologists. According to meteorologists, the maximum or daytime temperatures in the city will range between 35-36°C over the next few days, while the nights will be cooler as compared to the previous week.

The India Meteorological Department (IMD), on Sunday, recorded 36.4°C at its Santacruz observatory, while the Colaba observatory recorded 35.4°C. The relative humidity in Colaba and Santacruz was 83 per cent and 67 per cent, respectively. The temperature is expected to dip in the next few days, giving some relief from the October heat.

Climatologist Rajesh Kapadia of private weather blog Vagaries of the Weather said, "We are now facing the brunt of Mumbai's infamous ‘post-monsoon October heat'. On October 22, Mumbai's daytime temperature reached 37.4°C, the month's highest this year. From October 16, Mumbai has been witnessing hot weather ranging around 35°C every day. The last few days have been hotter than the normal average." The highest-ever recorded temperature in October was 38.6°C on October 17, 2015.

Explaining the phenomenon Kapadia said that as the monsoon withdraws, the South Westerly winds (monsoon winds) immediately change direction, and become hot inland East Winds. As the winds are easterly from the land, the cooler sea breeze, typical of Mumbai, is restricted. Hence the day gets warmer. "Looking at the present and forthcoming weather system changes, Mumbai can expect the weather to take a nip in the air after November 10," Kapadia said.

He added that for Mumbai, currently the temperature day-night range is 36-22°C. "The next few nights can be expected to remain around the 21-23°C range. For Mumbai, below 20°C is a nip. So we can expect it to "chill" below 20°C around the Diwali days."

Meanwhile, the overall air quality in Mumbai continues to remain in the moderate category, which has slightly improved as compared to last week when it remained poor. As per the Central Pollution Control Board (CPCB) SAMEER app, the overall air quality index (AQI) of Mumbai on Sunday was 154. Only Navy Nagar Colaba (IITM station) and BKC (MPCB station) recorded air quality in the poor category with an AQI value of 268 and 246, respectively.

As per the daily world polluted city ranking by Swiss firm IQAir, on Sunday Mumbai slipped to the ninth position from the second spot last week, whereas Delhi climbed up to the third position. Kolkata took the 12th position.

"Since the monsoon bid the city goodbye, the pollution levels and the air quality has been technically termed as poor. That means the AQI (measured taking into consideration all the polluting factors) is around 170-200. This is bound to happen, seasonally, as the strong monsoon winds are no more blowing off the pollutants, and thus the stationary trapped air accumulates the smog for several days. Lately, with the winds gearing up, we see the AQI levels dropping slightly," Kapadia explained.

37.4°c
Highest daytime temperature recorded this Oct