One way to measure how to get the best deal is to look at the Sales Price to the Original List Price ratio. In other words, how much is the seller getting compared to their asking price. In the busy Spring market, Sellers are getting close to 100% of their asking price.
When are sellers getting the least? January. If you back up 30-45 days, that means the contract was written in December. If a seller has had their place on the market for any length of time and the end of the year is approaching, they are more likely to cut a deal and get it under contract before the holidays and winter sets in.
So when is the Best time for you? The best time is when the timing is right for you. Don't buy a place in December just because you are getting a good deal if the place isn't right for you. And don't get caught up in a multiple offer situation in the Spring if don't know what you want. Do your homework. Know what you want. Buy when the right place comes along for you and move fast when you do.