Surprisingly, no. Rain brings contaminants in the air down onto your car, leaving a grimy layer of pollutants when it evaporates. If you wash with Spark Rain Repel before it rains, those contaminants won’t stay on your car and you’ll be way ahead of the game. And if you absolutely can’t make it in time, the second best option is right after a rainstorm … or even during! Spark Folsom is always open, even when it’s raining.