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Parts of India are currently facing a severe heatwave, with daytime temperatures crossing 45 degrees Celsius. States like Madhya Pradesh, Punjab, Bihar, Uttar Pradesh, Jharkhand and Delhi-NCR are experiencing extreme heat. But the problem is not ending after sunset. Even at night, many homes and bedrooms are becoming very hot. As a result, people are waking up tired, sweaty, and uncomfortable despite air-conditioners and fans being turned on.
Nights Getting Hotter, Says IMD
Doctors and health experts say that extreme heat is disturbing sleep and affecting health. Many people are experiencing headaches, tiredness, brain fog, dehydration, and disturbed sleep because their bodies are unable to cool down properly at night. Moreover, the observation by India Meteorological Department (IMD), shows that nights in India are getting hotter much faster than days.
According to the IMD data and a Climate Trends study from May 2026, indoor temperatures in crowded city homes often stay between 31 degrees Celsius and 34 degrees Celsius even late at night. This situation is now being called a “Warm Night” crisis.
Why Is There Heat Even At Night?
Generally, the Earth cools down after sunset. During the day, the ground and buildings absorb heat from the sun and release it at night. But now, cities are not cooling properly, and the main reason is the Urban Heat Island (UHI) effect. It is a phenomenon where cities experience increasingly warmer temperatures than their surrounding rural areas. It is one of the most accelerating issues worldwide.
As cities today are filled with Reinforced Cement Concrete (RCC) buildings, concrete roads, asphalt and glass structures, this phenomenon is increasing. All these materials absorb a lot of heat during the day and slowly release it at night. Because of this, the surroundings remain hot for many hours after sunset.
Another major reason is the increasing use of air-conditioners. When millions of ACs run together, they release a huge amount of heat outdoors. According to experts, this can raise evening temperatures by another 4 degrees Celsius to 6 degrees Celsius. Additionally, humidity also worsens the situation as when the air is loaded with too much moisture, sweat can’t evaporate properly.
How Is It Affecting Sleep?
Several studies have revealed that for good sleep, the body temperature must naturally drop by around 1 degree Celsius. But when bedroom temperatures remain above 30 degrees Celsius at night, the body cannot cool itself properly. As a result, the heart works harder to push blood toward the skin to remove heat, leading to people waking up at night.