[Anchor]

The Korea Meteorological Administration has released its nationwide temperature statistics for July. Last month, the national average temperature reached 26.8°C (80°F), ranking as the third highest since the nationwide meteorological observation network was expanded in 1973. However, looking solely at nighttime lowest temperatures, this July's average hit an all-time high of 23.4°C (74°F). This is 2.2°C higher than the historical average. Such rising nighttime temperatures mean our bodies, exhausted from scorching daytime heat waves, have no time to recover.

Reporter Seo Donggyun has the details.

[Reporter]

Tropical nights in Seoul have already continued for 14 consecutive days.

Last night (August 4), the lowest temperature in Seoul dropped to 29°C (84°F), coming close to the 30°C (86°F) threshold for a "super-tropical night."

[Kim Hyun-ki / Dongjak-gu, Seoul: It is very hot at night just like during the day, and when you try to sleep with a heated body, you don't feel refreshed the next day.]

The European Centre for Medium-Range Weather Forecasts calculated the so-called "heat stress index," which affects the human body using global temperatures and humidity, over a 74-year period from 1950 to 2024.

Heat stress begins when the index value exceeds 26°C.

Looking at the average of the ten days with the highest index each year, heat stress has steadily increased.

Dividing it into daytime and nighttime, since the 1970s, daytime temperatures have risen by 0.27°C every decade, while nighttime temperatures have increased by 0.32°C, showing a steeper rise at night than during the day.

Examining the temperatures affecting the heat stress index, nighttime lowest temperatures have risen faster than daytime highest temperatures over the past decades due to the influence of clouds and water vapor.

Days experiencing both tropical nights and heat stress have surged since 2010.

In particular, the year 2024 saw four to five times more such days compared to the 1950s.

If the nights fail to cool down like this, it can impact our health.

[Kang Jae-heon / Professor of Family Medicine, Kangbuk Samsung Hospital: When body temperatures remain high at night, cardiovascular organs including the heart cannot rest, leading to increased blood pressure and faster pulse rates, which (long-term) raises the risk of developing cardiovascular diseases.]

The number of tropical night days nationwide is breaking historical records day after day this year.

As the nights, when the body should be recovering, are getting hotter at a faster pace, more caution and preparation are needed for heat wave measures during both the day and the night.

(Photo courtesy of: Kim Young-hwan | Video Editing: Kim Jun-hee | Design: Choi Haneul)