Is this year's summer weather in Korea really less hot?

Korea's summer is generally known for being very hot and humid. In particular, summer in Seoul has been a really tough time for those taking the subway to morning classes and for commuters during working hours. However, I've heard that this year is different. In the past, the subway was so hot that it earned the nickname 'hell train,' but this summer, there are rumors that it is less hot and humid than in previous years. I would like to hear the opinions of those who have experienced how the summer weather in Seoul is different this year. How did you feel about the weather this summer? Is the subway during rush hours still tough this year? I'm curious about how the changes in weather have affected daily life.