Nights across India in September 2025 were warmer than usual, with minimum temperatures rising well above the long-term average. The India Meteorological Department (IMD), in its monthly climate summary released, said that the month was among the warmest on record for night-time temperatures.
Record Night Temperatures
The average minimum temperature across India in September 2025 was 23.44 degrees Celsius, which is 0.63°C higher than the 1991–2020 normal of 22.80°C. The mean temperature, which averages daily highs and lows, stood at 27.51°C, 0.39°C above normal.
The average maximum temperature was 31.58°C, only 0.15°C above normal, showing that the warmth came mainly from higher night-time temperatures.
“This pattern indicates that the heat persisted through the night, limiting cooling after sunset,” said Dr. M. Mohapatra, Director General of Meteorology at the IMD. “Such trends are significant because they affect comfort levels, health, and energy demand.”
Since national records began in 1901, September 2025 ranked as the fifth warmest for average minimum temperatures and the seventh warmest for mean temperatures. The maximum temperature ranked 23rd, showing that daytime heat was not the main cause.
As per the IMD data out of 35 tracked cities, half experienced 20 or more nights with above-normal minimum temperatures. This means that for over two-thirds of the month, these cities did not cool down at night.
Diu had 29 warm nights, the highest in the country, followed by Patna, Srinagar, and Lucknow with 26 each. Other affected cities included Jammu, Dehradun, Guwahati, Panjim, Ranchi, Bhopal, Imphal, Kohima, Ludhiana, Jaipur, Gangtok, Agartala, and Kolkata.
In contrast, only 10 cities recorded above-normal daytime highs.
East and Northeast Stayed Hottest
The eastern and northeastern regions of India saw the sharpest temperature rise. The average minimum temperature in this region was 24.52°C, 0.82°C above normal, making it the third-highest since 1901.
The average maximum temperature there was 32.31°C, 1.59°C above normal, also ranking as the third-highest on record. This means both day and night temperatures were unusually high.
India received 193.6 mm of rainfall in September 2025, 15 percent above normal. The monsoon withdrawal began on September 14, three days earlier than usual.
Central and northwest India recorded much higher rainfall, while the east and northeast were drier. Central India got 255.3 mm (44 percent above normal), northwest India 134.2 mm (31 percent above normal), and east and northeast India only 195.9 mm (31 percent below normal).
Experts said this uneven rainfall may have influenced the temperature pattern. Less rain in eastern regions meant fewer cool nights, while high humidity in other areas trapped heat.
Weather Systems and Their Effect
The IMD reported four low-pressure systems over the Bay of Bengal during September, including one deep depression. These weather systems brought heavy rain to parts of Telangana, Odisha, and coastal Andhra Pradesh.
At the same time, three western disturbances passed through northern India. These systems, along with moisture from the Arabian Sea, kept humidity levels high.
This combination of humidity, cloud cover, and moisture prevented night-time cooling, according to IMD officials.
Broader Pattern of Warm Nights
IMD’s long-term data shows that September nights have been getting steadily warmer over the past few years. The average minimum temperature in 2024 was 23.79°C, followed by 23.68°C in 2023, and 23.52°C in 2021.
Researchers say rising night temperatures reflect changes in humidity, land use, and atmospheric composition. Cities, in particular, are more vulnerable because concrete and asphalt retain heat.
September 2025 was marked by warm, humid nights across India, especially in the east and northeast. While daytime temperatures stayed close to normal, the persistent night-time heat made it one of the warmest Septembers on record.
The IMD’s findings point to a clear pattern: India’s nights are getting hotter. For millions across the country, it means less relief after sunset, a sign that even after the rains, the heat no longer fades as easily as before.
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