"Spring and Autumn Abnormal High Temperatures: Last Year's Average Temperature Was the Second Highest on Record"

[Image source=Yonhap News]

[Asia Economy Reporter Eunmo Koo] Last year’s average temperature was recorded as the second highest ever. This was due to abnormal high temperatures in spring and autumn, which appear to have been influenced by global warming.

On the 3rd, the Korea Meteorological Administration announced that the average temperature last year, calculated based on weather observation data from 62 locations, was 13.3 degrees Celsius. This is the second highest since the nationwide observation network was established in 1973, following 2016 (13.4 degrees).

The unusually high temperatures from February to March and from early September to mid-October last year are cited as the reasons for the "second highest temperature ever." The average temperature from January to November was 14.4 degrees, the highest for the same period since 1973, while the December average temperature was 1.9 degrees, not significantly higher than the normal 1.5 degrees.

In February last year, a mobile high-pressure system influenced South Korea, and a south wind influx at the end of the month caused high temperatures nationwide. The average temperature at that time was 3.6 degrees, exceeding the normal temperature (1.5 degrees) by more than 2 degrees, making it the third highest February temperature since 1973. The highest temperature in February was 9.6 degrees, the second highest since 1973.

In March last year, the average temperature was 8.9 degrees, 2.5 degrees higher than the normal 6.4 degrees; the highest temperature was 14.9 degrees, and the lowest temperature was 3.4 degrees, all the highest since 1973. Due to the high temperatures, spring flowers bloomed early, with cherry blossoms blooming in Seoul on March 24, the earliest since observations began in 1922.

At that time, Arctic temperatures were lower than normal, causing a "positive Arctic Oscillation," which prevented cold Arctic air from descending into mid-latitude regions. Additionally, La Ni?a occurred in the Pacific, developing high pressure around South Korea, resulting in unusually high temperatures in March.

From early September to mid-October last year, the average temperature was 20.9 degrees, the highest since 1973. Even after entering autumn, a subtropical high-pressure system remained over the southern part of South Korea for an extended period, bringing warm south winds and causing the abnormal high temperatures during this period.

Last year was also notable for extreme temperature fluctuations within seasons. In January, the standard deviation of average temperature, indicating variability, was 5.3 degrees, the highest since 1973. From January 7 to 10, the daily minimum temperature broke records for the lowest ever for four consecutive days, and from January 21 to 25, the daily maximum temperature records were successively broken. In February, the standard deviations of average temperature and average maximum temperature were 4.5 degrees and 5.7 degrees, ranking third and second highest respectively since 1973.

Looking at spring, March had the highest temperature ever recorded, while April experienced both cold waves and early summer weather simultaneously. In May, the average temperature was among the eight lowest ever recorded. In autumn, the average temperature from early September to mid-October was exceptionally high, but then dropped sharply, with the first ice (October 17) and first frost (October 18) in Seoul observed 17 and 10 days earlier than usual, respectively. The standard deviation of average temperature in October was 5.1 degrees, the highest since 1973. The subtropical high-pressure system that brought a warm early autumn suddenly contracted, while a cold continental high-pressure system rapidly expanded, causing the temperature to change abruptly.

South Korea’s annual average temperature has gradually increased. Among the top 10 years with the highest annual average temperatures, eight occurred after 2000. Expanding the range to the top 20 years, 14 occurred after 2000.

This content was produced with the assistance of AI translation services.