Summer of discomfort

Mumbai close to heatstroke; temperature touches 40⁰ C

    If you’ve been feeling sweaty, sticky and completely ill at ease in the day and have been puzzled how the maximum temperature is only about 34 degrees Celsius, here’s the answer—the discomfort index (a combination of maximum temperature and humidity) reveals that in the first half of May, the city has been on the brink of a heatstroke.
    According to the Indian Meteorology Department (IMD), the discomfort index is a computed value that describes how hot or humid the weather ‘feels’ to an average person. “The discomfort index combines the temperature and humidity into one number to reflect the perceived temperature,’’ explains an official from IMD Pune. “It is, therefore, a better measure of how stifled a person feels than either temperature or humidity alone,’’ he adds.
    The discomfort index for the last week reveals that even though the maximum temperature was higher in Santa Cruz, the level of discomfort is more in Colaba, which has a higher level of humidity. For instance, on May 9, the discomfort index in Santa Cruz (temp: 37 degrees, relative humidity: 54 per cent) was 51 degrees. But on May 11, the discomfort index was the highest in the city (57 degrees) in Colaba, with a temperature of 34 degrees and 94 per cent humidity.
    ‘Maximum temperature in the city has been hovering around 35 degrees and humidity has been swinging between 65 and 90 per cent,’’ informs R V Sharma, deputy director general of IMD Mumbai. “The index is likely to rise with increase in humidity. An index of 55 degrees is the threshold. Anything beyond that is likely to cause a heatstroke across the city,’’ he adds.
    According to the weather bureau, humidity levels in the city change almost every half hour, which makes it difficult to calculate the highest discomfort index. “We can only take into account the maximum temperature of the day and the relative humidity at the time,’’ says an official from the disaster management cell of the BMC. “Mumbaikars should not unnecessarily remain outdoors for too long,’’ advised a weather bureau official.