Two visitors sleep on blankets laid out on the sand at Gyeongpo Beach in Gangneung, Gangwon Province, early Sunday. (Yonhap) A midsummer-like heat lingered Saturday night in Gangneung, Gangwon Province, as the city recorded its first tropical night of the year.A tropical night refers to a weather phenomenon in which the temperature does not fall below 25 degrees Celsius between 6 p.m. and 9 a.m. the following day.Early Sunday morning, members of a sea swimming club enjoyed a morning swim at Gyeongpo Beach in Gangneung. As the blazing sun rose over the horizon after a night of lingering heat, they dived into the sea to cool off. Sea swimming crews warm up before a morning swim at Gyeongpo Beach in Gangneung, Gangwon Province, early Sunday. (Yonhap) Sea swmming crews dive into the beach at Gyeongpo Beach in Gangneung, Gangwon Province, early Sunday. (Yonhap) Sea swimming crews take photo whlie swimming at Gyeongpo Beach in Gangneung, Gangwon Province, early Sunday. (Yonhap) According to the Gangwon Regional Office of Meteorology, the lowest temperature in Gangneung fell to 25 degrees Celsius at 5:02 a.m. before rising again. This year’s first tropical night in Gangneung was recorded on May 30, 19 days earlier than last year’s June 18. Two visitors dive into the beach at Gyeongpo Beach in Gangneung, Gangwon Province, early Sunday. (Yonhap) Clear and hot weather is expected to continue as a high-pressure system moves from west to east across the Korean Peninsula, bringing warm southwesterly winds. According to the Korea Meteorological Administration, daytime highs are forecast to climb above 30 degrees Celsius in most regions over the weekend, especially in the central regions.Weather officials advised people to check the heat-impact forecast and take precautions against heat-related illnesses.