Next winter, the website of the India Meteorological Department (IMD) will not just tell us the minimum temperature, it will feature the “chill index” — a measure of how cold we actually feel.
According to the weather forecasters, people often feel far colder than the actual temperature indicates. This is due to the wind chill factor. The IMD, as part of its Climate Services Programme under the Health and Climate Programme, plans to create an interactive website through which citizens can give their response on the “feels like temperature”. Based on these responses, the IMD will calculate the “chill index”.
For example, if the minimum temperature given by Met officials is 10°C, the website will ask citizens to quantify how cold they feel. Citizens can make their entries, anywhere between 9°C and 12°C, said Additional Director General of IMD B Mukhopadhyay, the lead scientist for the initiative.
“At present we are testing the system with random numbers. From next winter we will take inputs from the people,” he said.
Mukhopadhyay said that they decided to introduce the chill index as it was observed that people keep stating that they felt either more cold or less cold than the current temperature.
“This can be expressed in the interactive website, and we will calibrate their responses on their actual feeling of discomfort in the cold,” he added.
Just as the heat index is defined for summer, the wind chill index is defined for winter. “It is determined by temperature under various wind speeds and temperatures,” a Met official said.
Wind chill is usually calculated on the basis of various factors such as expected air temperature, relative humidity and wind strength at 5 feet — the typical height of a person’s face. This is calibrated with an understanding of how heat is lost from the human body on cold and windy days.
Scientists at IMD in Pune said that the project is at an experimental stage, but trial runs are already in progress in Pune and Delhi.