What is the constellation of May 13?

Taurus. Constellations were introduced into China from the west, and the Gregorian calendar is an international calendar, so constellations are calculated according to the Gregorian calendar. Taurus, the second house of the zodiac, is located in the east of Aries and the west of Gemini. May 13 is in this period, so May 13 is Taurus.