I'm interested in the answer as well for I did this first time, too. I'm thinking closer to real spring but I don't know.

It will take a month or 2 for them to start growing well if they've been stored right- in the dark and just above freezing and haven't dried out too much. They have to put down new feeder roots. Pot them up in damp not wet potting soil and place where it's warmer with indirect light. Gradually over a period of 2 to 3 weeks move them closer to direct sunlight. Watch the water too much and they will rot until they have put down new feeder roots.

I have never had success doing things this way. I think because my basement is too warm. However my Sister-in- law always stores her geraniums in a cold cellar and it works for her. I grow my geraniums under lights all winter and take cuttings in the spring. As with all gardening it's whatever works for you