Let me be more precise
At dormancy (February for instance ) up to early spring you may go for cleft, bark, side, whip.. grafting
As soon as sap starts flowing and the buttons appear about forming, it's time for T and chip-budding. In the Mediterranean, farmers commence these two budd methods in April/ May and go through August.
You may go beyond that and if done properly the grafts will hold but will not shoot out new growth until next spring.
Good luck
Francisco