The virtues of having a camping tarp are obvious when it rains, but you may not realize that it's really nice to have one even when the sun is shinning as the tarp will provide guaranteed shade as well. At night, being under a tarp will result in a temperature increase especially if you have a lantern going. You can also situate a tarp as a lean-to if you need a wind break just by staking one side all the way to the ground. The real trick to a tarp is getting your rope high enough so the tarp doesn't sag too low.