I am sure that this is the time to plant Garlic. In NZ they always say to plant garlic on the shortest day of the year. It's pretty cold now, but garlic needs some cold weather to germinate.
I am not sure about the Onions tho'. Mark found onion seedlings in the garden centre,and optimistically brought them home. I have duly planted some of them, and so far they are not dead. That's got to be a good thing.
It's a waiting game now, I'll keep you posted.