I set myself goals, but after the first couple of months was unable to attain them as I hit a huge plateau. (But I recently found out that I'm low-thyroid actually, unbeknownst to me, that my dr thinks has been going on for awhile, so that is probably the reason for my stall).
That being said though, I've tried for new goals now that hopefully my thyroid is getting back into its zone. Mine are similar to yours:
240 by June 30 (leaving on a trip to the caribbean!)
230 by labour day
I do think your first goal especially is attainable, btw, but only if you don't hit a plateau (second goal is probably a bit of a stretch). Otherwise, all bets are off. But even if that happens, keep on going regardless. In other words, don't let the goals (and their attainment or failure) be the most important thing. The most important thing is the plan you have for achieving (or not) them.
I think they're very reasonable and very motivating. Because I have a lot of weight to lose, I generally make them every 20 or so lbs.
I started at 307 and my first goal was to get to 280. I reached that number recently and made the second one 260. I think after 260 I'll make it 250 and so on.
Set them all the time. Usually mine is more daily caloric and macronutrient targets. I find that if I'm able to stay on these, the scale weight takes care of itself.
I want to lose 15 more pounds by the end of June.....Yay 230 pounds! Then, I want to be at 199 pounds before September 5th (My first day of teaching for next school year)... Do these seem reasonable to you?
If you reach 230 pounds by the end of June, that would mean you have just over nine weeks to lose the 31 pounds that would bring you to 199 pounds by Sept. 5. This equates to more than 3 pounds per week, which seems a little overambitious to me.