Happy hours is time, when all earnings are multiplied. It means, if the normal kill price is 1000$, on Happy Hours with x1.3 bonus you’ll earn 1300$. Completing Van Heist mission as Cops is even better, because the earning will be 5000*1.3=6500$!

Current bonus

18:00-19:00 (GMT+1): x1.2

19:00-21:00 (GMT+1): x1.3

21:00-22:00 (GMT+1): x1.1