Solar longitude
90°
Classification
Principal term · 气 qi
Month boundary
Does not open a month
Definition
What Summer Solstice marks
The season behind the name
Summer Solstice marks the Northern Hemisphere’s longest daylight, followed by gradually shorter days.
These names grew from seasonal observation and farming practice. They describe a traditional seasonal sequence, not a weather forecast for every region.
Summer Solstice begins at the instant the Sun reaches 90 degrees of apparent ecliptic longitude. It is one of 24 equal 15-degree divisions of the solar year, so its Gregorian position changes only slightly from year to year.
As a qi term, Summer Solstice marks the alternating mid-month point in the solar-term sequence. It does not open a solar branch month, and it does not open a lunar month.
The time is shown in China Standard Time (UTC+8). A reader west or east of that zone may see the same instant fall on a different local civil date.
Three pentads · 三候
Seasonal observations
Each traditional pentad spans about five days and names a seasonal sign associated with that part of the term.
- First pentad
Deer shed their antlers
鹿角解
- Second pentad
Cicadas begin to sing
蜩始鸣
- Third pentad
Pinellia begins to sprout
半夏生