The Lukewarm Secret: Is Your Car Wash Temperature Ruining Your Paint?
by AutoExpert | 15 January, 2026
Turns out, water temperature is kind of a big deal when washing a car—who knew?
Using water that's too hot can crack windows or wreck the paint, especially in winter. And in summer, hot water just leaves annoying streaks and spots everywhere. Cold water has its own issues too. Besides potentially freezing on the car (fun times), it barely loosens up caked-on dirt and grime.

Best bet? Don't even bother washing when it's below 32°F outside. If there's no choice, wait until afternoon and use water that's just slightly warm—not hot, not cold.
When summer rolls around and it's pushing 90°F or hotter, wash early in the morning or wait until evening. Never wash a car that's been baking in the sun all day. That's just asking for trouble.

The Lukewarm Sweet Spot
Water around 100°F is pretty much perfect for car washing, any time of year. It's warm enough to help the soap actually work—loosening dirt without messing with the wax or leaving streaks behind. Got tar stuck on there? Lukewarm water with some car shampoo and a clay bar takes care of it no problem.
Honestly though, just washing regularly matters way more than stressing about the exact temperature.

How Often to Actually Wash It
Every two to four weeks is the standard answer. Drive through dusty areas or construction zones a lot? Probably lean toward every two weeks.
In winter, hitting the underside with some warm water helps clear off road salt before it becomes a rust problem. Regular weather? Once a month is fine.
Just don't use dish soap. Seriously. It strips off the protective wax and can mess up the trim. Stick with actual car shampoo and everyone's happy.