Delhi’s average Air Quality Index (AQI) improved sharply to the satisfactory category on Friday after the capital recorded its highest single-day October rainfall in four years, with the Safdarjung observatory receiving 61.4 mm of rain in the 24 hours ending at 8.30 am.
The city’s average AQI stood at 90 at 9.30 am on Friday, down from 222 in the poor category at 4 pm on Thursday, according to the Central Pollution Control Board. The improvement followed widespread showers across Delhi, with several weather stations recording more than 40 mm of rain.
India Meteorological Department data showed that Lodhi Road received 63.4 mm of rainfall, followed by Ayanagar at 55.4 mm, Chhatarpur at 53.5 mm, the Ridge at 50.3 mm and Palam at 43.1 mm. Jharoda Kalan recorded the highest rainfall among the stations, at 89 mm, as of Friday morning.
The latest rainfall was the highest single-day October total recorded at Safdarjung since October 9, 2022, when the station received 74 mm. Nearly half of Delhi’s rainfall total for October was recorded during the 24-hour period ending Friday morning.
The rain also brought a marked change in daytime temperatures. Delhi recorded a maximum temperature of 25.4°C at Safdarjung on Thursday, 5.6 degrees below normal and the lowest maximum temperature for an October day in four years. The previous lower maximum was recorded on October 8, 2022, when the temperature stood at 23.4°C.
The minimum temperature did not fall by a similar margin and stood at 17.2°C on Friday, 1.1 degrees above normal. Cloud cover and high humidity can restrict the loss of heat from the surface, limiting the fall in night-time temperatures.
October is generally among Delhi’s drier months as the city transitions from the southwest monsoon season towards winter. However, recent years have included several spells of heavy October rain. Safdarjung recorded 122.5 mm in October 2021, 128 mm in October 2022 and 89.3 mm in October 2025. Between 2017 and 2020, the station recorded either no rainfall or negligible precipitation during October.
The month’s cumulative rainfall has now reached 123.3 mm, compared with the monthly normal of 15.1 mm. This represents a surplus of 108.2 mm, or approximately 717 per cent, according to historical data from the IMD.
IMD officials attributed the rainfall over Delhi and other parts of northwest India primarily to an active Western Disturbance. These eastward-moving weather systems originate in the Mediterranean region and adjoining areas, travel across West Asia and bring moisture into northwest India, often producing cloud cover, rain and thunderstorms.
The weather system triggered rainfall across parts of Haryana, Uttar Pradesh, Uttarakhand and adjoining areas. The IMD also referred to the remnant depression of Very Severe Cyclonic Storm Arnab, which was located over Chhattisgarh and adjoining Odisha on Thursday and was expected to weaken into a well-marked low-pressure area. The two systems were influencing different parts of the country, with the Western Disturbance driving rainfall activity over northwest India, including Delhi.
The IMD forecast further spells of light to moderate rain accompanied by thunderstorms and lightning on Friday and issued an orange alert for the entire capital. Partly cloudy skies were forecast for Saturday, followed by mainly clear skies from Sunday.
