Mumbai witnessed an unusually hot start to October, with Colaba recording a maximum temperature of 37.4°C on Friday, the highest October temperature recorded in south Mumbai in at least 13 years. The temperature was 5.6°C above normal, while high humidity added to the discomfort across the city.
The heat comes as Mumbai enters the final phase of the southwest monsoon, with changing wind patterns and atmospheric conditions contributing to the rise in temperatures.
Colaba records 37.4°C, Santacruz 36.9°C
The Colaba observatory recorded 37.4°C, while the Santacruz observatory, Mumbai's baseline weather station, recorded a maximum of 36.9°C, around 4.6°C above normal.
Colaba also recorded a minimum temperature of 27.5°C, about 2.2°C above normal, early Friday morning.
The latest temperature was unusually high for the beginning of October. On October 8, 2024, Mumbai had recorded a maximum of 36.5°C during another spell of October heat.
Why is Mumbai experiencing October heat?
According to India Meteorological Department (IMD) scientist Sushma Nair, the rise in temperatures is linked to the transition associated with the withdrawal of the southwest monsoon.
As the monsoon withdraws, wind patterns begin shifting from westerlies to easterlies. This can delay the arrival of the sea breeze that usually helps keep Mumbai's temperatures relatively moderate.
An anti-cyclone near Mumbai has also contributed to the rise in temperatures, resulting in warmer daytime conditions across the city.
Mumbai may remain hot for the next few days
The IMD expects daytime temperatures to remain around 35°C to 37°C over the next two to three days. High humidity could make the conditions feel even more uncomfortable for residents.
The weather is expected to gradually change as the post-monsoon pattern becomes more established.
How unusual is 37.4°C in October?
While 37.4°C was the highest October temperature recorded in Colaba in 13 years, it is not the highest temperature ever recorded there during the month.
The all-time October record at Colaba is 39.5°C, recorded on October 22, 1968.
The latest reading therefore remains below the historical record but is significant because of how early in October the temperature was recorded.
Delhi, Chennai also see temperatures in the mid-30s
Mumbai is not the only major Indian city experiencing warm conditions. As the country moves through the post-monsoon transition, several metropolitan cities are recording daytime temperatures in the mid-30s.
According to weather data for October 4, 2026, the expected temperatures are:
| City | Maximum temperature | Minimum temperature |
|---|---|---|
| Delhi | 35°C | 24°C |
| Mumbai | 34°C | 26°C |
| Chennai | 35°C | 26°C |
| Bengaluru | 30°C | 20°C |
Delhi weather: Maximum around 35°C
Delhi is expected to record a maximum temperature of around 35°C and a minimum of 24°C on October 4. The capital is likely to remain largely clear, with temperatures rising during the afternoon.
Some forecasts have placed Delhi's maximum closer to 37°C, indicating that the capital could continue to experience significant daytime heat.
Mumbai weather: Heat and humidity continue
For October 4, Mumbai is forecast to record a maximum of around 34°C and a minimum of 26°C. While this is lower than the 37.4°C recorded at Colaba on Friday, humidity could make conditions feel warmer.
The city's recent heat spell follows the unusually high temperature recorded at Colaba and comes amid the ongoing transition from monsoon to post-monsoon conditions.
Chennai weather: Warm and humid
Chennai is also expected to remain warm, with temperatures around 35°C during the day and 26°C at night.
Given its coastal location, the city could experience a combination of heat and humidity, making the afternoon conditions feel warmer than the actual temperature.
Bengaluru remains comparatively cooler
Bengaluru is expected to be significantly cooler than the other three metros, with a maximum of around 30°C and a minimum of 20°C.
The city could also see cloudy conditions and light rain, offering some relief from the heat experienced in other major urban centres.
Delhi and Chennai among hottest major metros
Based on the October 4 forecast, Delhi and Chennai are expected to record the highest maximum temperature among the four cities at around 35°C, followed by Mumbai at 34°C. Bengaluru is expected to remain the coolest, with a maximum of around 30°C.
The contrasting temperatures are influenced by each city's geography, elevation, humidity and prevailing atmospheric conditions. Coastal cities such as Mumbai and Chennai can feel considerably warmer because of humidity, while Bengaluru's higher elevation generally keeps temperatures more moderate.
As October progresses, weather conditions are expected to gradually shift with the establishment of the post-monsoon pattern across different parts of the country.
