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Nepal is expected to experience above-average maximum temperatures for the fourth consecutive year. The government has issued warnings about potential heatwave outbreaks across various regions of the country.
The Department of Hydrology and Meteorology has forecasted, starting from Friday and extending over the next three days, the likelihood of heatwaves spreading in some Terai areas of Koshi, Madhesh, Bagmati, Gandaki, Lumbini, and Sudurpashchim provinces.
According to the department, the maximum temperatures in these areas are expected to reach or exceed 38 degrees Celsius.
The World Health Organization defines a heatwave as conditions where the maximum temperature exceeds 40 degrees Celsius in flatlands and over 30 degrees Celsius in hilly regions.
Associate Professor Madan Sigdel from the Central Department of Hydrology and Meteorology at Tribhuvan University identifies continuous maximum temperatures above 40 degrees Celsius as the primary indicator of heatwaves in Nepal.
What Is This Heatwave Like?
Meteorologist Rozen Lamichhane from the Department of Hydrology and Meteorology stated that this year marks the fourth heatwave alert since the summer season began.
He said, “Approximately 11 heatwave warnings have been issued across 2023 and 2024.”
“This condition is expected to persist for some time,” Lamichhane added.
“If temperatures drop or it rains in the coming days, new advisories will be promptly released. The heatwave will gradually subside with cloud cover and weather changes.”
He noted that this year’s heatwave, compared to previous years, is not severe.
A Decade of Above-Average Temperatures
The average maximum temperature during Nepal’s summer season is 26.7 degrees Celsius. However, for the past three years, temperatures have consistently remained above this average.
A location’s average temperature is determined based on long-term 30-year measurements.
Data collected from 68 measurement stations nationwide confirmed 2023 as the hottest year of this decade.
According to department records, that year’s temperatures were 0.73 degrees Celsius above average.
In 2024 and 2025, temperatures rose 0.51 and 0.48 degrees Celsius above average, respectively.
In its seasonal assessment of May, the Meteorological Department indicated a 55 to 65 percent chance that maximum temperatures at many locations will remain above average between May 31 and October 1 this year.
The International Centre for Integrated Mountain Development (ICIMOD) estimates an increase of 0.5 to 2 degrees Celsius in maximum temperatures across the Hindu Kush Himalaya this year.
Historical data shows that from 2008 to 2018, Nepal experienced above-average maximum temperatures for most of the time.
Records of Highest Temperatures
The year 2016 has been recorded as the hottest since temperature measurements began in Nepal in 1981.
The average temperature that year was 27.57 degrees Celsius, 0.87 degrees above average, with elevated temperatures persisting for two years thereafter.
“The next highest average temperature after 2016 was recorded in 2010,” said meteorologist Ashok Bakharel.
However, he noted that the maximum temperature record of 2016 remained unbroken until recently.
On June 16, 2016, a temperature of 42.5 degrees Celsius was recorded in Bharatpur, Chitwan.
According to Bakharel, the highest temperature ever recorded in Nepal was 46.4 degrees Celsius in Dhangadhi in 1995.
In the same year, 45.8 and 45.2 degrees Celsius were recorded in Semari, Nawalparasi and Bhairahawa respectively.
On June 15, 2024, a temperature of 45.2 degrees Celsius was recorded in Tikapur.
In 2023, temperatures above 44.8 and 43 degrees Celsius were observed respectively in Damkoli, Rampur, and Parchwanipur.
The Meteorological Department has noted that the coolest summers of this decade were recorded in 1981 and 2020.
What Is Causing the Heat?
Associate Professor Madan Sigdel of Tribhuvan University’s Department of Hydrology and Meteorology noted that this year’s reduced rainfall does not necessarily mean a significant drop in minimum temperatures.
“The developing El Niño phenomenon in the Pacific Ocean is likely to bring dry conditions and higher-than-average temperatures to our region,” Sigdel explained.
He also emphasized climate change as an indirect but significant factor contributing to these conditions.
“We need to consider atmospheric processes involving soil, ocean, and sky, within which climate change plays an important role,” he said.
“Temperatures reaching 38 to 40 degrees Celsius annually have become common in the Terai,” Lamichhane stated.
“Notably, in recent years, temperatures have significantly risen in the mountain valleys and gorges as well.”
