Why Delhi feels like 51°C but isnt ? Wet-bulb temperature explains why it feels so
The Indian Meterological Department (IMD) said that the capital's heat index or feels like temperature crossed 50 degree celcius, highest reading recorded this year.
PTC News Desk: Delhi has been reeling under intense heatwave and the air feels extraordinarily strange. It does not just feel hot, it feel heavy, sticky almost solid, as though the heat has weight and is leaning against your skin.
The Indian Meterological Department (IMD) said that the capital's heat index or feels like temperature crossed 50 degree celcius, highest reading recorded this year. Yet the thermometer outside read only 41.3 degrees Celsius. So which number is true? Both are. And the gap between them is one of the most important ideas in modern climate science.
Delhi felt much hotter than the actual temperature because of high humidity. While the air temperature was 41.3°C, the heat index — which measures how hot it feels when humidity is taken into account — reached 51.3°C.
A key factor behind this discomfort is the wet-bulb temperature, which combines heat and humidity. The IMD recorded a wet-bulb temperature of 29.77°C. When humidity is high, sweat cannot evaporate easily from the skin, making it harder for the body to cool down. As a result, temperatures feel much higher than they actually are. For example, an air temperature of 44°C with high humidity can feel like 50-51°C.
Delhi is experiencing unusually muggy weather because moist southwesterly winds from the Arabian Sea are bringing moisture into northwestern India. At the same time, the monsoon has not yet reached the city. Normally, monsoon rains from the Bay of Bengal help lower temperatures, but in their absence, Delhi is getting humidity without enough rainfall, leading to sticky and uncomfortable conditions.
The IMD said humidity levels remained between 35% and 63% and are expected to stay high over the next few days, keeping the weather hot and humid.
Some relief may arrive on June 29, with rain and thunderstorms likely and temperatures expected between 29°C and 39°C. Similar weather is forecast for June 30, with temperatures ranging from 28°C to 38°C. The monsoon is expected to reach Delhi after July 4, bringing more sustained relief from the heat.