Study finds heat waves in Türkiye at strongest levels in 75 years

Heat waves in Türkiye have sharply intensified over the past 75 years, with the summers of 2023 and 2025 recording the most intense events on record, according to a study by researchers at Istanbul Technical University (ITU).

The study, presented at the European Geosciences Union (EGU) conference, analyzed changes in heat waves across Türkiye between 1950 and 2025 using the Heat Wave Magnitude Index daily (HWMId), a metric based on daily maximum temperatures that measures the intensity of extreme heat events.

Researchers found a pronounced upward trend in both the frequency and severity of heat waves.

Average summer temperatures, which ranged between 22 and 23 C (72 and 73 F) during 1970-90, climbed to 24-25 C (75-77 F) after warming accelerated in the early 2000s.

The average summer temperature reached a record 26.1 C (79 F) in 2024.

The study found that heat wave intensity has increased at an even faster rate than average temperatures.

Compared with the 1980-2009 reference period, the average magnitude of heat waves in 2023 was more than seven times higher, while the figure for 2025 was nearly 11 times higher, making the two summers the most intense heat wave seasons since 1950.

By comparison, although 2024 was the hottest summer on record based on average temperatures, its heat waves were less intense than those recorded in 2023 and 2025. Researchers said this shows that record-high seasonal temperatures do not necessarily coincide with the most intense heat waves.

The study said heat waves result from complex interactions among atmospheric blocking patterns, warm air advection, elevated sea surface temperatures, drought and soil moisture conditions.

The research was conducted by climate scientist Baris Onol and meteorological engineer Tolga Karakaya at ITU's Department of Climate Science and Meteorological Engineering.

The researchers said the findings point to a fundamental shift in the climate regime across Türkiye and the eastern Mediterranean, underscoring the need to improve extreme heat forecasting and strengthen climate adaptation measures.

In a separate study examining future climate projections, the researchers estimated that the annual number of heat wave days could rise substantially under the UN Intergovernmental Panel on Climate Change's high-emissions scenario.

Between 2021 and 2050, the number of heat wave days is projected to increase to about 16 days a year in Istanbul, Ankara and Konya, 18 days in Antalya and 23 days in Izmir, up from an average of three to five days a year between 1976 and 2005.

For 2051-80, the projections rise to about 38 days a year in Istanbul and Ankara, 40 days in Antalya and Konya, and 53 days in Izmir.