When is the peak time for houses coming on the market?

I feel like I've seen everything on the market in my area for my prices range and I am getting frustrated waiting for something new to come on. Roughly, is there a peak time for properties to go on the market or is it just in dribs and drabs? It's been at least 2 weeks since I saw something new appear and we have the money and are renting and I just want to get on with it :-)