India's southwest monsoon has picked up speed after its delayed arrival in Kerala, but the bigger question now is how quickly it can reach North India before a strengthening El Niño begins influencing rainfall patterns later in the season.

While the India Meteorological Department (IMD) expects the monsoon to advance rapidly across southern and eastern parts of the country over the next several days, meteorologists are closely monitoring developing El Niño conditions in the Pacific Ocean that could affect rainfall during the second half of the season.

The monsoon has already covered Kerala and is moving steadily across peninsular India. If current conditions remain favourable, weather experts expect it to reach eastern states such as West Bengal, Bihar and Jharkhand by around mid-June before progressing further north.

For Delhi, Haryana, Punjab, western Uttar Pradesh and adjoining regions, the wait could extend until the final week of June or the beginning of July, in line with the monsoon's normal progression pattern.

Until then, North India is likely to depend on pre-monsoon thunderstorms, western disturbances and local weather systems for relief from soaring temperatures.

El Niño remains the key concern

Despite the monsoon's encouraging start, scientists say El Niño remains the biggest weather factor to watch this year.

The climate phenomenon, linked to warming waters in the equatorial Pacific Ocean, is currently weak but forecast to strengthen in the coming months. Historically, stronger El Niño events have often coincided with below-normal rainfall across parts of India, particularly during the latter half of the monsoon season.

That means the pace at which the monsoon advances during June could become increasingly important, especially for northern and central states that rely heavily on seasonal rainfall for agriculture and water supplies.

Meanwhile, pre-monsoon activity is expected to remain active across Delhi-NCR, Punjab, Haryana, Rajasthan, Uttar Pradesh, Madhya Pradesh and Maharashtra over the next few days. Gusty winds, thunderstorms and scattered rainfall are forecast, bringing temporary respite from the intense summer heat.