Janice:

It's too late by about a month. The weeds also would bother me. I only plant over black weed barrier or plastic. If you plant melons all you'll grow on that plot this yr is weeds.

It's probably too late to get much of a harvest, but if you're willing to do the work and fertilize and water well, and if the weather cooperates, you might get one or two fruits per plant. It could be a good learning experience. I live in a similar climate zone on the border of zone 6 and 5 in southwest Ohio. I have grown icebox watermelon s (sugar baby, tiger baby) in half whiskey barrels, and usually get my first melons in early August. But I start my seeds indoors around May 1 and put them outdoors around Memorial Day. Melons can take from 70 to 110 days to maturity from planting outside. So if you want to try, pay close attention to the DTM. 75 days from now will be mid September. Will the weather be warm enough in your area to ripen melons in September (night temps of 55-60 at minimum)? Look at the DTM for the varieties listed on this website.

Here is a link that might be useful: Watermelon varieties

Technically, it probably is too late but if you have the right mindset that you probably won't get a lot of melons but want to experiment, I say go for it. If not, you could go for another crop that grows faster that you love just as much. I remember seeing a woman, on a garden show, who did plant her garden late because she had recently moved and she had a great garden. She lived in 5a or 5b. I believe she started right before July 1st. You never know, it might be a warmer fall. I planted a few things late last year because I had a similar situation as you did where an extra plot was abandoned. I got lots of zukes but the winter squashes just didn't make it in time. Still, it was a fun learning experience.

If you raise melons, make it a productive exercise. Melons are by far the most disease susceptible plants to raise in the following years. The first year is free.