Delhi sets new record: Wettest October since 1956

With 6.5mm of rainfall being added in the last 24 hours, Delhi has now received 128.2mm of rainfall, going past 122.5mm of rainfall it received last October to so far make it Delhi’s wettest October since 1956, when Delhi had received 236.2mm of rainfall

Delhi received 6.9mm of rainfall between 8:30 am on Monday and 5:30 pm on Tuesday, taking the amount of rain in the national capital to 128.6mm thus far this month, making it the wettest October in the city since 1956, India Meteorological Department data (IMD) data show. This is 751% of the normal monthly mark of 15.1mm.

Commuters out in the rain near Lajpat Nagar bridge in New Delhi. (Raj K Raj/HT Photo)

Overall, this is the fourth wettest October in Delhi since 1901, when IMD started keeping records. The wettest October recorded in the Capital was in 1954, when the city received 238.3mm of rain, followed by 1956 (236.2mm) and 1910 (185.9mm). Last October, the city received 122.5mm of rain.

Delhi is likely to see more rain activity, with IMD forecasting isolated showers in the city on Wednesday. However, the rain is likely to stop from Thursday , Met officials said.

“Most of the rain activity has finished and only isolated parts may receive a shower now. We do not expect any rain after that till October 17,” said IMD scientist RK Jenamani, adding that this year’s October rainfall activity showed a longer duration of impact, stretching from October 7-11, whereas last October, the rainfall was limited to a period of around two days.

“Last October, there was a major 24-hour spell of 87.9mm in a single day. This year, we have seen strong cloud cover and good, incessant rain from October 7 to 11, with peak rain activity occurring on October 8, when rain was recorded almost for an entire day,” he said.

By Sunday, Delhi had crossed the annual rainfall mark for the Capital, which is 774.4mm, and by 5.30pm on Tuesday, the city had received 811.4mm of rain. Of this, the city received only 516.9mm of rain in the monsoon months of June to September -- normally, Delhi receives 640.4mm of rainfall in the monsoon months.

While Delhi has received more than normal rain this year, last year saw Delhi receiving a total of 1,512.4mm rain – the highest for the Capital since 1933, when Delhi had received 1,534.3mm of rain.

Overall, October so far has emerged as third wettest month for Delhi, behind September, which received 164.5mm of rain and July, which received 286.3mm of rain.

According to Jenamani, this year, the intensity of the weather system was strong largely due to the interaction of a western disturbance with a tropical system moving from the Arabian Sea towards Rajasthan and Delhi-NCR. “This meant easterly winds from the Arabian Sea were constantly feeding this western disturbance and moisture kept coming in, keeping the clouds intact over NCR. This has kept Delhi’s maximum temperature to around 24 degrees Celsius or lower for three consecutive days and the difference between the maximum and minimum temperature was also fairly low, making this October more intense in terms of extreme weather,” he said.

On Tuesday, Delhi’s maximum temperature was 30.1°C -- four degrees lower than normal for this time of the year. This was more than the maximum of 23.6°C recorded on Monday, 24.1°C on Sunday and 23.4°C on Saturday.

In terms of air quality, Delhi’s air quality index (AQI) deteriorated slightly on Tuesday, with the city recording a reading of 66 and returning to the ‘satisfactory’ category after two consecutive ‘good’ air days. The Central Pollution Control Board (CPCB) classifies an AQI of 50 or lower as ‘good’, between 51 and 100 as ‘satisfactory’, between 101 and 200 as ‘moderate’, between 201 and 300 as ‘poor’, between 301 and 400 as ‘very poor’ and over 400 as ‘severe’.