The internal colour of the melon depends upon the exposure of the fruit to sunlight. In a few cases you may find the interior to not be perfectly red in colour which could be because the fruit was not exposed to proper sunlight but it will still be sweet in taste. An uncut melon can last longer on a counter when it is stored in a spot away from direct sunlight than it would in the fridge. Once you have cut your melon make sure you place it in an airtight container and refrigerate it.