What type of grafting do you want to do? I think its a good time to do bark grafting but I haven't checked to see if the bark is slipping lately. I know I did some on March 31, 2007 and it worked great. I am not a grafting expert but I'd still do whip grafting too if I had any to do. The key would be to make sure the scion wood is dormant.

Jade,

Its perfectly fine to graft now using whip and tongue.

I find the bark grafts even easier. In my yard I would guess some of the trees have slipping bark and some don't (actually branches in the same tree even).

I've done both types of grafts using dormant wood into June and have had success. Plumfan has done grafts much later than that using non-dormant scions.

The main issue is the quality of your scion wood.