IMD plans colour codes to explain ‘uncomfortable’ temperatures

IMD officials said that as the heat bearing capacity of people differs from place to place, a new study will be carried out to help residents understand their discomfort through the colour of their respective location rather than comparing temperatures.

K S Hosalikar, deputy director of the IMD, said that like the Air Quality Index is explained with colours revealing severity, the same principle will be applied in case of recording temperatures.

“The adaptability differs. Mumbai residents cannot stand the same temperature as Pune residents can. What might be considered dangerous in Pune, would be above severe for Mumbaikars. Hence, a colour coding system that will simplify the weather and explain the dangers,” said Hosalikar. IMD officials said the base line or the mean temperature of each location would be calculated and a new colour code will be prepared on that. Especially to understand heat and cold waves.

A heat wave condition is declared when the temperature is more than 45 degrees Celsius. But for a coastal station like Mumbai, the temperature has to be above the normal temperature by 4.5 degrees Celsius and more than 37 degree Celsius to qualify for a heat wave condition, IMD officials said.

“Say for instance, Mumbai’s mean temperatures is 37 degrees Celsius. Now, this 37 degrees Celsius would be represented by say orange and as the temperature rises, the shade of colour would get darker indicating the severity. In Mumbai, 39 degrees Celsius would mean dangerous, 42 degrees Celsius would suggest critical conditions and anything above that, which is mostly likely to be indicated by dark red, would reveal very severe conditions,” Hosalikar explained.

“This colour band system is one method through which any layman can understand temperature reading and its affects,” a senior IMD official said.

The System of Air Quality and Weather Forecasting and Research (SAFAR), which records Mumbai’s AQI, gives the health hazard reading and charts out precautions to be taken for the corresponding colour and temperature. The IMD’s latest figures suggest that 2016 was the hottest year in a over a century since 1901. A recent study conducted to find the Heat Index, mainly in urban India, places Mumbai in the “very hot” category.

Last month, the Met department had predicted that it will be hotter than usual during the summer in 2017 till June. In its summer outlook for this year, the IMD said that temperatures — minimum, maximum as well as the mean — are likely to be “above normal” till June in every meteorological subdivision of the country. Northwest India and the plains near the Himalayas are likely to face particularly warmer summer this year with temperatures likely to be more than 1 degree Celsius above normal. More than 17 observatories across the state have already recorded temperature above 40 degrees Celsius.