In some cities, a car wash is a matter of aesthetics. But a Chicago car wash is virtually a matter of your vehicle’s survival. With harsh winters and sweltering summers, the city’s weather patterns don’t take kindly to exposed paint and unmaintained undercarriages. Here’s how—and how often—to take care of your car in every season of the year.

Fall: Every Couple of Weeks

The season when the temperatures have fallen but the first snow hasn’t hit is the prime time to get your car ready for the city’s brutal winter. To prep for the snow, wash every inch of your vehicle, including the undercarriage. Make sure to apply a coat of wax and wax sealant—this will protect the paint, which in turn protects the body from oxidation and rust. 

Finally, seal the undercarriage, paying special attention to the brake and fuel lines. You can purchase a sealant to do this at home, or find a Chicago auto detailing shop to do it for you. This crucial step protects some of your car’s most important parts from the salt and other chemicals they’ll face when the snow starts to accumulate.

Winter: As Often as Possible

Winter is perhaps the worst time to own a car in the city, since snow and salt on the roads pose a big risk for rust, and few car washes in Chicago are open in freezing temperatures. Most experts concede that although washing your vehicle once or even twice a week in winter is optimal, in reality drivers may only be able to get to a car wash every couple of weeks. 

When you do go, make it count. Pay particular attention to the underside, because rust on the undercarriage can eventually reduce the structural integrity of the entire vehicle. Try to maintain a good coat of wax throughout the season to ward off paint oxidation. And to avoid freezing yourself out of your car, periodically lubricate your locks, trunk, and gas cap with WD-40 and apply a silicone spray to the weather stripping around the doors.

Spring/Summer: Two to Three Times a Month

The snow might have melted, but that doesn’t mean you can stop maintaining your car. During nice weather, drivers can get away with washing their cars around three times a month. However, rain poses a whole new issue. In urban areas such as Chicago, precipitation can bring contaminants that can create permanent marks in a car’s paint if they’re not washed away. That means you can’t let Mother Nature do the work for you: counterintuitively, you should wash your car right after it rains.