Like Bunny said - its just a number - one way to quantify your body -- but if you are interested in optimum bodyfat loss and your time frame is September -- that's easy 3 months -- what will get you there w/ the best results is using diet & training consistently (esp diet) for efficient burn rate - takes about 3 weeks to set up a consistent schedule and at that point, if you stick with it, you'll just see the stuff drop off. Don't look at it as a particular burn rate per week, but rather just keeping a consistent program going over the whole course of the summer and that consistency will translate into bodyfat loss. But by the same token, if you follow the exact same diet & training, your body will eventually adapt - then you would want to tweak your program a bit to encourage a readaption by your body for continued loss.
To that end -- take a look at your program - does your diet provide enough fuel for your training and not leave you feeling exhausted, but also not overfill you w/ stuff that isnt' burned by your activity? If not, first look for an efficient balance of that, then run w/ it for a few weeks to see how it works for you. If it works, then keep going. Make sure you aren't running on a constant low % of carbs because that will stall you out quickly. I suggest using a "carb cycle" or a regular interval of carb "refeed" every couple days, and keep any cheats to one / week.