South Korea experienced an unusually hot spring in 2026, featuring the highest average temperature for May on record [1].
These temperature spikes signal a shifting climate pattern that brings extreme heat earlier into the year, potentially disrupting agricultural cycles, and public health infrastructure during the transition to the monsoon season.
According to the Korean Meteorological Administration, the period from March to May was the second-hottest spring since observations began [1]. The data indicates that the heat was not limited to a single month, though May stood out as the most extreme [1].
This warming trend contributed to the earliest heat wave ever recorded in certain areas of the country [1]. These high temperatures coincided with the onset of the monsoon season, creating a volatile weather pattern characterized by both heavy rains and oppressive heat.
In addition to daytime heat waves, the region saw the earliest occurrences of tropical nights during the monsoon period [2]. Tropical nights, where minimum temperatures remain high, prevent the environment from cooling down, increasing the physical strain on the population.
Officials said the specific temperature data was released on May 2, 2026, as the country began to track the anomalies [1]. The combination of record-breaking May averages and early-season heat waves suggests a trend of intensifying summer conditions that begin well before the traditional peak of the season [1, 2].
“May 2026 had the highest average temperature on record.”
The emergence of record-breaking temperatures in May and the early arrival of tropical nights suggest that the traditional boundaries of South Korea's seasons are blurring. When extreme heat arrives before the monsoon season typically peaks, it creates a 'double burden' of humidity and high heat, which can increase energy demands for cooling and elevate the risk of heat-related illnesses earlier in the calendar year.
