Delhi and parts of the NCR woke up to shallow fog on Saturday morning, an uncommon sight for late March. Several areas recorded reduced visibility, with the lowest at 1,200 metres between 7.30 am and 8.30 am at Safdarjung and between 8 am and 9 am at Palam, according to the India Meteorological Department (IMD).

Delhi also experienced a minimum temperature of 13 C Celsius on the morning of Saturday, which is the lowest temperature in the last 10 days of March in the last 15 years. This is 3 C Celsius lower than the previous day.

Weather factors behind the fog

Experts attribute the fog to a mix of recent rainfall, high moisture levels and calm winds overnight. “Shallow fog formation in late March is not very common but can occur when there is sufficient moisture near the surface and clear skies during the night allow temperatures to drop,” Hindustan Times quoted an IMD official as saying.

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Mahesh Palawat, president at Skymet Weather, echoed the explanation. “Shallow fog was seen across parts of Delhi-NCR as the minimum temperature dropped to 13C, and it rained over the past couple of days. So, there was heavy moisture in the air along with clear skies that led to condensation and foggy conditions,” he said.

Daytime relief, but mixed trends continue

As the day progressed, the fog lifted, and the temperature increased to a maximum of 27.4 C. However, the overall conditions remained cooler than those experienced in the last days of March. The minimum and maximum temperatures have been below normal in recent days because of western disturbances.

At other places, the following were the maximum and minimum temperatures: Palam - 26.3 C and 13.5 C; Lodhi Road - 27 C and 13 C.

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Outlook: Gradual warming ahead

The IMD has predicted the same to continue over the next couple of days, with cool mornings and slightly warmer afternoons. Light rain, along with thunderstorms and lightning, is expected on Monday.

Northwesterly winds are expected, and they may help clear the fog by reducing moisture. A gradual increase in temperatures is expected after March 24, along with dry conditions towards the end of the month.

Meanwhile, the air quality in the national capital has dropped to a moderate level, recording an AQI of 119, up from 93 the day before, due to calm winds and early morning temperature inversion.