Summer Climate
Summer Climate of 2024
1. Characteristics of Korea’s Summer Climate
Characteristics of Korea’s Summer Climate
The summer weather on the Korean Peninsula is typically hot, humid, and highly variable, with noticeable increases in temperature and concentrated rainfall.
Due to the effects of climate change, extreme weather events such as heatwaves, torrential rains, and typhoons are becoming more frequent and intense.
1 ) Temperature
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June: High temperatures due to the influence of migratory high-pressure systems.
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July–August: Continued hot weather likely under the influence of the North Pacific High.
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Average temperature: Around 24–27°C
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Temperatures are highest in July and early August, with many heatwave days where the daily maximum exceeds 35°C.
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In recent years, climate change has led to rising average temperatures and an increase in the number of heatwave days.
2) Rainy season
(Jangma)
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Heavy rainfall occurs nationwide from late June to mid-July, known as the monsoon season (Jangma).
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It is caused by a stationary front formed where the North Pacific High and the Okhotsk High meet.
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After the monsoon ends, heatwaves and tropical nights intensify.
3) Humidity
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The average humidity in summer is about 76%, indicating a generally humid climate. Especially in July and August, humidity levels rise to around 78–79%.
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Due to the hot and humid conditions, the perceived temperature (heat index) often feels higher than the actual air temperature.
4) Heavy Rainfall (Localized Downpours)
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In mid-July and mid-August, near the end of the monsoon season, heavy rainfall often occurs in short periods; this period is called the heavy rain (concentrated downpour) season.
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Heavy rainfall is defined as when more than 30mm of rain falls within an hour, more than 80mm falls in a day, or when daily precipitation reaches 10% of the annual total.
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Korea experiences frequent heavy rainfall, especially localized downpours.
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These heavy rains commonly occur when moist southwesterly winds flow in as stationary fronts or low-pressure systems pass over the region, or when typhoons move through.
5) Typhoon
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Typhoons occur relatively frequently in August because sea surface temperatures must exceed 27°C in higher-latitude waters for typhoons to form.
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Each year, about 10 typhoons approach Japan and the Korean Peninsula, with 3 to 4 making landfall in Korea.
2. Summer Climate of Korea
in 2024
Analysis of Korea’s Summer Climate (June–August) in 2024
1 ) Temperature
a. Average Temperature
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The nationwide average temperature during the summer of 2024 was 25.6°C, which is 1.9°C higher than the average of 23.7°C.
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This is the highest since records began in 1973.
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Top 5 Summer Average Temperatures: 1) 2024: 25.6°C, 2) 2018: 25.3°C, 3) 2013: 25.2°C, 4) 1994: 25.1°C, 5) 2023: 24.7°C
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b. Early Summer
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From mid-June onward, temperatures remained consistently above average. Even during the monsoon season, when rainfall typically lowers temperatures, temperatures were generally higher than usual.
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Warm and humid air continuously flowed into Korea via southwesterly winds, and due to high humidity, nighttime temperatures did not drop significantly, leading to the occurrence of tropical nights.
c. Mid to Late Summer
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From late July to late August, persistent warm Tibetan High and North Pacific High systems covered Korea, maintaining high daytime temperatures.
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As a result, the average temperature in August was 2.8°C above the normal level.
d. Heatwaves and Tropical Nights
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The nationwide average number of heatwave days was 24.0, which is 2.3 times higher than the average of 10.6 days, ranking 3rd highest on record.
→ (1st) 2018: 31.0 days, (2nd) 1994: 28.5 days, (3rd) 2024: 24.0 days
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The number of tropical nights was 20.2 days, 3.1 times the average of 6.5 days, marking the highest ever recorded.
→ (1st) 2024: 20.2 days, (2nd) 2018: 16.5 days, (3rd) 1994: 16.5 days
2) Sea Surface Temperature
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In 2024, the sea surface temperature reached 23.9°C, which is 1.1°C higher than the average of 22.8°C for the past 10 years (2015–2024), marking the highest temperature during that period.
3) Precipitation
a. Characteristics of the Jangma
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The nationwide average precipitation during summer was 602.7 mm, which is less than the average of 727.3 mm.
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Typically, about 50% of summer rainfall occurs during the monsoon season, but in 2024, rainfall was even more concentrated during this period.
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In 2024, 78.8% of the summer precipitation fell during the monsoon — the highest proportion recorded since 1973.
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The nationwide monsoon rainfall totaled 474.8 mm, which is 32.5% (118.1 mm) higher than the average of 346.7 mm.
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Rain and clouds developed strongly as moisture flowing along the edge of the North Pacific High collided with cold air descending from the north along the stationary front.
→ This monsoon season was characterized by frequent, intense rainfall over narrow areas.
b. After the Jangma Season
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Outside the monsoon period, clear skies dominated under high-pressure systems, resulting in less rainfall than average for the same period.
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After the monsoon ended, the upper-level jet stream that triggers surface low pressure shifted northward. Under the influence of high pressure, localized surface heating caused atmospheric instability, leading mainly to scattered showers.