As summer sets in with sunny weather and high temperatures seemingly here to stay after a long, indecisive warm spell, overshadowed with occasional rainfall. Experts warn temperatures this week will rise further and well above seasonal norms.

Professor Orhan Şen, a prominent meteorological expert and academic from Istanbul Technical University, said the temperatures would rise up to 8 degrees Celsius above the seasonal norms and warned the public about possible health risks. Şen told Anadolu Agency (AA) that the summer of 2016 is expected to be the hottest in recent years due to several factors including global warming causing a 2-degree temperature rise, solar flares reaching unprecedented levels and the El Nino weather system.

Şen said the temperatures would gradually rise and for Istanbul, the country's most populated city, they might exceed 34 degrees Celsius later this week. "Starting from today, temperatures will rise to very high levels, especially in Istanbul and most of Turkey." The meteorological expert warned Muslims fasting in the holy month of Ramadan to stay indoors if they have health problems. Muslims abstain from eating and drinking from dusk to dawn during Ramadan, and the fasting month falling in the summer poses an additional challenge, as a longer day means a longer fast.

The weather forecast from the state-run General Directorate of Meteorology shows sporadic rainfall today and tomorrow for western and northern Turkey, and across the country temperatures will not fall below 21 degrees Celsius. On Thursday, save for the northeastern Black Sea region and eastern cities, the weather will be sunny, with temperatures predicted at 29 degrees Celsius for Istanbul and 37 degrees Celsius for Aydın, the western city with the highest predicted temperature.