Mumbai
“Fast Climate Transition in Mumbai. This speed of transition is more interesting climatologically than simply calling it “October heat.”
2 October: Mumbai — A remarkably fast seasonal transition
2 October: Mumbai abruptly entered October heat. Colaba 37.4°C (+5.6°C) and Santacruz 36.9°C (+4.6°C). Santacruz observations also show relative humidity dropping as low as about 41% that day
The mechanism is important: as the monsoon circulation weakened, winds shifted from moist westerlies toward easterly/land flow, while an anticyclone near Mumbai delayed the cooling sea breeze.
Then came the equally rapid deterioration in air quality. Mumbai's overall AQI rose to 111 on 2 October, with Worli at 178 and Colaba 143, after generally remaining below 80 during the rainy months.
Vagaries would phrase the AQI mechanism carefully as: "temperature inversion can trap pollutants near the surface '',
But it should not be presented as the sole cause of this particular AQI rise without vertical-Weak winds, loss of rain washout, drier air/dust and changing post-monsoon circulation were also important.
That gives a strong sequence to note:
29–30 Sep: Withdrawal thunderstorms → 2 Oct: 37°C Heat + humidity drop → 3 Oct: Monsoon withdrawal → early October: haze/AQI deterioration.
This week also start a Maharashtra October heat. Malegaon has already reached 38.4°C, 5.9°C above normal.
Maharashtra — Final Monsoon Status: State rainfall finished at 804.4 mm against 994.5 mm normal: −19%, (just inside IMD's “normal” classification rather than deficient, whose threshold begins at −20%.)
Twenty-one districts finished deficient. Particularly striking were Solapur −58%, Hingoli −49%, Jalna −48% and Parbhani −40%..
While Nashik +33% and Palghar +21% were in excess.
