Delhiites experienced an overcast and chilly day after the city recorded the highest single-day December rainfall in 101 years. The city received 41.2 mm of rain between 8.30 am on Friday and 8.30 am on Saturday, marking the highest single-day December rainfall in 101 years.

According to the India Meteorological Department (IMD), the Capital had last recorded the highest-ever rainfall on a single day in the month on December 3, 1923, at 75.7 mm. While rain in December is not unusual, it is usually light. As per IMD data, Delhi usually sees 8 mm of rain during the month over half a day. The rain in the city over the past 24 hours is over five times that.

The rains also made December 2024 the fifth-highest in terms of monthly rainfall since records began in 1901. In December 2024, Delhi logged 42.8 mm, the highest in the last 27 years when 71.8 mm of rain was seen in the month.

“The cumulative 24-hour rainfall ending at 8.30am today is the second-highest since 1901 at Safdarjung. December’s monthly rainfall is now the fifth-highest. The 24-hour cumulative rainfall refers to the precipitation recorded over the past 24 hours ending at 8.30am IST on the given date,” the IMD official explained. The rainfall largely attributed to an active western disturbance interacting with easterly winds, transformed the usual dry chill of December into an anomaly.

“The interaction between a very active western disturbance and a cyclonic circulation on the east, along with a few other factors, has brought about this unusual weather. November and December are the two driest months in Delhi. During these months, it is usually a western disturbance that brings rain to the capital. It is the different weather systems clashing that lead to heavy downpours,” an IMD scientist said. “Another western disturbance is expected around January 1, but that may not bring rain,” IMD further explained.

The IMD has issued a yellow alert for Delhi, predicting more showers for Sunday  in the capital, Noida, Gurugram and other places in the national capital region. The weather department has forecast very dense fog for Sunday, with the maximum and minimum temperatures expected to settle at 17 and 9 degrees Celsius, respectively

Heavy rainfall coupled with gusty winds continued to lash Delhi in the early hours of Saturday. Several areas, including Palam, Safdarjung, Lodi Road, Mehrauli, and Gurugram, reported uprooted trees, resulting in significant disruptions. In Sector-9, RK Puram, a portion of a road caved in, causing a motorcycle and a car to fall into the cavity.

The last time December rains were this intense was in 1997, when the total monthly precipitation was 71.8mm. Going further back, the highest December rainfall was recorded in 1901 at 77.2mm, followed by 1967 (69.5mm) and 1936 (68.1mm). IMD classifies up to 15.5mm of rainfall in 24 hours as “light rain”, 15.6-64.4mm of rainfall as “moderate”, 64.5-115.5mm as “heavy rainfall” and 115.6-204.4mm as “very heavy rainfall”.

Delhi witnessed incessant rainfall since Friday morning causing severe waterlogging and traffic snarls in several parts, leading to the mercury dropping in the National Capital. In June this year, Delhi has recorded 228.1 mm of rain in the 24 hours in one of the wettest spells the capital has recorded causing waterlogging in several parts of the National Capital.

The minimum temperature, recorded early Saturday morning, was 12.7 degrees Celsius at the Safdarjung weather station. This was 6 degrees above normal. The maximum temperature was 15.8 degree Celsius. This was five degrees below the normal.

Amid the rain, Delhi witnessed some improvement in the air quality, which remained in the ‘moderate’ category, with an Air Quality Index (AQI) of 139. This is both because of the rain and a slight increase in wind speed.

The Air Quality Early Warning System (AQEWS) for Delhi has forecast that the AQI may even dip into the “moderate” range over the weekend, before deteriorating again early next week. “The air quality is likely to be in the poor category on Sunday. The air quality is likely to be in the very poor category on Monday. The outlook for subsequent six days is that the air quality is likely to be in very poor category,” the AQEWS bulletin said.

The India Meteorological Department has issued a ‘yellow’ alert for the weekend, predicting “light rain/ thunderstorms”. Meanwhile, North India, including the capital Delhi, will see a chilly start to the New Year, with the weather office predicting a significant drop in minimum temperatures across several regions. Heavy rains at the fag end of the year will only intensify the ongoing cold wave conditions in the first week of 2025. As intermittent rain continues in several parts of Northwest India, the IMD has predicted a fall in the minimum temperature by 3-5 degrees Celsius in the next two days.