Longest day is a turning point
After xiazhi, the temperature will continue to increase. Just like Winter Solstice is start of "nine nine"-a system to record the following 81 days-in winter, this year, Tuesday marks the beginning of the "nine nine" of summer.
Chinese people used to count the days in periods of nine, and then summarize the conditions during each period in songs. One example of a summer nine nine song describes the increasingly warmer weather following the Summer Solstice, before it finally starts to turn cold.
"In the first and second nine, you always need a fan in the hand. In the third nine, you can find ice water as sweet as honey. Your clothes are always soaked with sweat in the fourth nine. You can feel gentle wind blow the branch in the fifth nine. The sixth nine is a good time to relax in a cool place. During the seventh nine you need to be covered with quilt when sleeping. Don't catch a cold in the eighth nine. Everybody finds their coat in the ninth nine."