You mention closing sometime between June and August but you didn't mention whether you have a contract on a property already. Whether you do or don't, locking in a rate - simply put - is a gamble. If rates go down and you are locked in - you are stuck with your higher rate. If rates rise, as they did recently, then you gambled a lucky hand and have yourself a lower rate. What you need to do is talk to your mortgage representative and find out if there are penalties to reconfigure your package if you lock in and rates drop. Some banks have a waiting period before you can reapply. Others charge a fee to switch rates. All banks work differently. Now, here's something else to consider: If rates drop or rise a fraction of a point whether you have locked in or not is only a matter of a couple dollars a month. What you should find out from your lender is whether you can refinance soon after being issued your loan and what the charges are to do this. (Some banks just charge a reappraisal or processing fee.) So, if rates drop considerably after you close, you might find that refinancing within the year can save thousands over the long run. Again, all banks operate differently, so talk to your bank representative, ask questions and find out the details. Best of luck with your home buying adventure.