The national average temperature last month was 22.2℃, 0.8℃ higher than the normal 21.4℃.
According to the analysis of the characteristics and causes of the climate in June 2026 released by the Korea Meteorological Administration on the 3rd, warm air flowed in during the early and middle parts of last month, pushing temperatures above the normal for 1991–2020. In particular, on the 18th to 20th, minimum temperatures rose significantly above normal, causing abnormal heat in most regions nationwide. Abnormal heat refers to cases falling within the top 10% compared to normal.
At the end of the month, cold air moved in. As a result, the average temperature for last month was 0.7℃ lower than last year's 22.9℃, which was the hottest June.
The average temperature last month was higher than normal, and the nationwide number of heat wave days was 0.6, about the same as the normal 0.7 days. Considering that the nationwide number of heat wave days in June 2024 and 2025 was 2.8 and 2, respectively, there were fewer heat waves this year. For the first time since observations began in 2022, there were also no tropical nights in June (minimum nighttime temperature of 25℃ or higher).
Nationwide precipitation last month was 95.4 mm, less than the normal 148.2 mm. With generally clear weather continuing, the number of days with precipitation was 6.9, three fewer than the normal 9.9 days. As heavy rain fell nationwide on the 19th to 20th, 64.4% of June's precipitation was concentrated in that period.
The rainy season began in Jeju Island and the southern region on the 30th of last month. Compared with normal, Jeju Island is 11 days late and the southern region is 7 days late. The Korea Meteorological Administration said, "The reason the rainy season started late this year is that the North Pacific high, which produces rainy-season rain, advanced northward late, and in the meantime cold air continued to move down, preventing the rainy-season front from forming properly."