00000000 00000000 00000000 00000000
The value in bold will be known as pw; it is essentially p % 65536.
Wurmple's evolution does not depend on time of day, despite what many guides say. In fact, the evolution is determined by taking pw % 10. If the remainder is less than 5, Wurmple will become a Silcoon, and if it is greater than or equal to 5, it will become a Cascoon.- bulbapedia
so that is it , it's very confusing