Why it's raining in Delhi despite monsoon end?

Delhi, Gurgaon, Noida and surrounding areas of the National Capital Region (NCR) experienced heavy rain and thunderstorms on Monday, October 12, leading to a sudden drop in temperatures. The India Meteorological Department (IMD) predicted moderate to heavy rain and thunderstorms for the next two to three hours, with a temperature fall of around 1-2 degrees Celsius in Delhi's maximum temperature over the previous 24 hours.

Although the rain provided temporary relief from the warm early October conditions, it does not necessarily signify the arrival of winter. The unsettled weather situation in northern India is attributed to atmospheric systems like Western Disturbances and troughs, which can bring rain even after the southwest monsoon begins to withdraw.

Western Disturbances, moving eastwards from the west, can cause cloud formation, rain, thunderstorms and hail in northwestern India. Troughs, elongated zones of low atmospheric pressure, can encourage air to rise, fostering cloud development and rainfall.

Hailstorms can form within strong thunderstorm clouds when upward air currents carry water droplets into extremely cold atmospheric layers, causing them to freeze and develop into ice pellets. The intensity of a thunderstorm, available moisture, and cloud temperature profile impact whether hail develops. Isolated hailstorms and strong winds were recorded in Himachal Pradesh, Uttar Pradesh, and Uttarakhand on October 11.

The current rain spell is expected to be brief, with the IMD warning of rain and thunderstorms continuing for two to three hours on Monday morning. Delhi's forecast predicts partly cloudy skies and no rainfall over the following six days. However, other parts of northern India may experience unsettled weather for several days, with Uttarakhand, Himachal Pradesh, Punjab, and Haryana forecasted to receive varying levels of rain.

Delhi's temperature forecast suggests a slight cooling effect after the rain, with daytime temperatures expected to rise to around 32-34°C and night temperatures remaining around 23-25°C. Despite the immediate rain, Delhi is not expected to experience sustained winter conditions.