Battery voltage low. Will start and turn over but will still read low voltage?

Hello, it is likely that the rain could have splashed up and caused the belt to slip on the pulleys, resulting in the gauge message and possible low charging system output. This is merely a guess, but consistent with weather conditions while driving. A full check of your charging system should be performed, as well as checking the belt to ensure it is not slipping. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops