Delhi to receive rain this evening, but bigger monsoon spell begins Tuesday
Delhi is likely to see rain this evening as the monsoon trough edges back over the plains, with the IMD flagging a bigger, more widespread spell from July 21. A yellow alert is in place for July 21 and 22 across Delhi-NCR.
Delhi could see rain this evening as the monsoon trough shifts back over the plains, but the IMD says the real spell of widespread rain begins from July 21, with a yellow alert in place for the 21st and 22nd. (Photo: Reuters)
Delhi's break from the monsoon is ending in stages.
Some rain has already touched parts of the capital, more is expected this evening, and the India Meteorological Department (IMD) says the real, widespread spell arrives from Tuesday, July 21, when a yellow alert kicks in.
WHAT IS MONSOON TROUGH, AND WHY DOES ITS POSITION MATTER?
The monsoon trough is a long belt of low pressure that runs across northern India through the rainy season, roughly from Rajasthan to the Bay of Bengal. It works like the spine of the monsoon.
Wherever it sits, moist winds converge, rise, cool and turn into rain clouds.
For over a week, it had drifted north towards the Himalayan foothills, a pattern meteorologists call a break monsoon, which is why Delhi stayed hot, humid and largely dry even as the season carried on elsewhere.
It is now sliding back south, over the plains.
WHEN WILL IT RAIN IN DELHI TODAY?
According to the IMD, Delhi can expect very light to light rain in many places through the day, with isolated pockets seeing moderate showers.
Thunderstorms, lightning and gusty winds of 20 to 30 kmph, touching 40 kmph in bursts, are likely during the morning and afternoon, followed by another spell of light rain during the evening or night.
One independent meteorologist has projected a narrower window of moderate to heavy showers hitting only patches of the NCR this afternoon and evening, which fits how patchy this kind of rain usually is, though that specific timing has not been issued as an official IMD figure.
WHY IS THE BIGGER SPELL COMING FROM JULY 21?
A low-pressure system that had been sitting over West Bengal has been pulling moisture inland from the Bay of Bengal, while winds from the Arabian Sea feed the same system from the west.
Together, these currents are dragging the trough south.
That is the mechanism behind the thick band of rain-bearing cloud currently stretching from West Bengal and Bihar through Uttar Pradesh towards Punjab and Chandigarh, and it is why the IMD has issued a yellow alert for Delhi-NCR for July 21 and 22, when rain is expected to turn more widespread and sustained.
WHY DOES THIS MATTER BEYOND THE NEXT FORECAST?
Delhi's stretch of hot, rain-starved days was a direct result of the trough sitting in the wrong place.
Its return to the plains is not just about wet evenings; it marks a genuine revival of the monsoon over north India after the break, with the potential to chip away at the rainfall shortfall built up while the trough sat near the hills.
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