Delhi: 384.66mm rain for July helps keep mercury in check

The monthly normal rainfall mark for July is 209.7mm, which means that this year, Delhi logged an excess of 83% rain over the long-period average.

Delhi recorded rain on 19 out of 31 days in July this year, and the city received 384.66mm rainfall over the course of the month — the third most for July over the last two decades, India Meteorological Department (IMD) data shows.

Delhi recorded rain on 19 out of 31 days in July this year. (Raj K Raj/HT PHOTO)

The monthly normal rainfall mark for July is 209.7mm, which means that this year, Delhi logged an excess of 83% rain over the long-period average (LPA). IMD’s monthly rainfall data showed in the last two decades, Delhi received more rain in July only in 2003 (632.2mm — the all-time record) and 2021 (507.1mm).

The consistent rain and overcast conditions also kept the Capital’s maximum temperature in check, with a monthly average maximum temperature of 34.7 degrees Celsius (°C) — Delhi’s lowest since 2016, when it was 34.5°C.

The LPA for the maximum temperature in July is 35.6°C, while the minimum is 27.5°C.

Kuldeep Srivastava, scientist at IMD, said that this July, the monsoon trough was largely south of Delhi, but stayed close enough to bring light rain to the city. “Largely, we’ve seen that the trough has been south of Delhi-NCR and that brings easterly winds, which raise humidity but only lead to localised light rain,” he said.

However, the month’s defining rain spell came on July 8 and 9, when the city recorded over 250mm rainfall. “On July 8 and 9, we had the trough passing through Delhi and also had a western disturbance. The combination of these two weather systems brought extreme rain over Delhi and largely brought excess rain this month,” Srivastava said.

Mahesh Palawat, vice president at the private weather forecaster Skymet, said Delhi-NCR and large parts of northwest India received large excess in terms of rain in the first half of the month, with the second half seeing limited activity, as the monsoon trough was closer to central India.

“We saw floods and excess rain after the spell of rain between July 7 and 9, when the combination of the monsoon trough being in northwest India, a western disturbance and even a cyclonic circulation over central Pakistan, all interacting. Much of the monthly rain was recorded during this period. The monsoon trough has returned north in the last few days, bringing moderate rain again on July 25, but the intensity was far less as compared to the first half of the month,” he said.

This year, the monsoon arrived earlier than normal, reaching Delhi on June 25 – two days before its normal date. This meant there was excess rain in June too, with 101.7mm being recorded through the month – 37% over the monthly LPA of 74.1mm. In fact, six of the seven months so far this year have now seen excess rainfall, with the only month being an exception being February, when no rain was recorded through the month.

However, Delhi is likely to witness a slow start to rain in August, with only isolated drizzles expected in parts of Delhi till August 2. Light to moderate rain may occur in some parts of Delhi from August 3 until August 6, officials said.

Palawat said that while Delhi has chances of recording moderate rain between August 3 and 7, early models for August show the monsoon will be fairly weak over northwest India.