IMD Fixes Delhi Rain Data Error, Explains How Rainfall Measured

The India Meteorological Department (IMD) is a weather agency that measures how much rain falls.

IMD uses tools called rain gauges, which collect rainwater and measure its depth in millimetres.

Some gauges are read by people, while others send data automatically by computer.

Delhi has several rain-measuring stations, including Safdarjung, Palam, and Lodhi Road.

Recently, IMD said Delhi had received more rain in August than normal.

Then IMD said that number was wrong and fixed it.

After the fix, Delhi had received less rain than expected for August.

IMD counts a day's rain from 8:30 in the morning until 8:30 the next morning.

Measuring rain that already fell is different from forecasting rain that might fall.

That is why the agency can correct old numbers even while issuing new weather alerts.