Sambok (삼복), the Dog Days of Summer | The Korean Way

https://thekoreanway.wordpress.com/2010/07/29/sambok-%EC%82%BC%EB%B3%B5-the-dog-days-of-summer/

Sambok refers to the time period encompassing the hottest three days of the year … (This time period is also sometimes referred to as 복날, bok nal, which is loosely translated “dog days of
summer.”)

Sambok occurs over the course of a month and the dates are set using
the lunar calendar. … they occur between the beginning of the sixth and seventh months on the lunar
calendar… with chobok (초복), the first important date of sambok.

Ten days after chobok the second date occurs; it’s jungbok (July 29 this year on our calendar). Then 20 days after jungbok, the third (and last) date occurs. This one is called malbok….

Traditionally this was a time for farmers to relax some before the harvest, and they might use this time to take a short vacation.