Due to South Korea’s hot and humid temperatures, cases of malaria have been on the rise, with the Korea Disease Control and Prevention Agency reporting 367 cases as of Tuesday.

Though the number of malaria cases so far this year is half of last year's total figures, the agency on Wednesday noted there has been an unusual surge in malaria cases in Seoul and that it is possible this year's total figures could pass last year's. In previous years, malaria cases were normally reported in Gyeonggi Province, Gangwon Province and Incheon. A malaria alert has been issued for Greater Seoul and Gangwon Province.

As of Tuesday, the agency reported that 66 individuals have been diagnosed with malaria in Seoul, and that 13 districts -- Gangdong, Mapo, Jongno, Gwangjin, Gangseo, Eunpyeong, Seongbuk, Gangbuk, Dobong, Nowon, Jungnang, Yangcheon and Guro districts -- have been labeled as high-risk areas for malaria. Other than Seoul, Gyeonggi Province has seen a total of 196 malaria cases, while Incheon has recorded 55, according to the KDCA.

The surge of malaria patients came as the weather agency declared the end of South Korea’s monsoon season on Tuesday and said the heat is likely to continue for some time. According to the Korea Meteorological Administration, daytime temperatures Thursday are expected to range between 30 to 36 degrees Celsius nationwide, with the weather feeling as hot as 35 C the rest of the day. Morning temperatures are also expected to reach 30 C nationwide, hinting at tropical nights in most parts of the country from Wednesday evening to Thursday morning.

Tropical night refers to the phenomenon in which the low temperature remains above 25 C between 6 p.m. and 9 a.m.

Korea has seen a number of tropical nights over the past few days. As of Wednesday, Seoul has seen tropical nights for 10 days straight, while Gangneung in Gangwon Province and northern parts of Jeju Island have seen tropical nights for 12 and 25 consecutive days, respectively.

According to the weather agency, the lowest temperature recorded in Seoul Tuesday night was 27 C, while Gangneung and Jeju Island saw temperatures as low as 30.4 C and 27 C.

The weather reports came as most parts of the country saw heat wave warnings on Wednesday, with the average nationwide daytime high expected to reach 37 C.

In most parts of the country, heat wave warnings were issued at the “alert” level on Wednesday. Heat wave warnings at the “alert” level -- the third level in Korea’s four-tier system -- are activated when the highest apparent temperature is forecast to exceed 35 C for two consecutive days or more.

Seoul expected daytime temperatures on Wednesday to reach as high as 33 C, while other cities like Ulsan and Daegu were to see temperatures reach as high as 35 C and 37 C, respectively.

According to the KMA, hot and humid temperatures along with tropical nights are expected to continue as the atmosphere over Korea is covered by the Tibetan anticyclone and the North Pacific anticyclone. Because of this, the weather agency added that heat wave warnings and humid tropical nights will persist throughout the country for some time.