Why are my watermellons busting open before there ripe

Question

some are ripe but i lose more than half because there cracked open

Answer 1

It depends how much rain you get. Were I live, we have had the wettest summer I can remember in a long time.

Too much water will EXPLODE both water melons and Cantaloupe melons.

I have actually heard the popping noise in my garden in similar years in the past, when the melons blow, they really fly open

Answer 2

I suspect drought followed by heavy rain. If you water or irrigate them follow an even schedule or you get the same result. Tomatoes are another plagued by this.  RScott