Car washing in hot weather: our dos and don’ts for the best results

car washing in hot weather
Try to wash your car one panel at a time when the weather’s hot (Picture iStock/rclassenlayouts)

Car washing in hot weather, or even on a warm sunny day for that matter, can become a long, drawn out and frustrating process. Even sunshine on a relatively cool day can cause trouble when you want to clean your car.

Cars heat up astonishingly quickly in the sun. According to researchers at Stanford University in the US, on a day when the temperature is just 20 degrees C, a car’s interior will get to 38.9 degrees C within 30 minutes. If the outside temperature is 24 degrees C, it will reach 42.9 degrees C in 30 minutes.

The car’s mainly metal bodywork soaks up heat just as effectively, causing water to evaporate quickly as soon as it’s spread over your motor. The result will leave a dirty tide mark of combined shampoo and dirt. And when you do manage to rinse that off, it’ll dry quickly again, leaving spots on your paintwork from impurities in the water.

How to wash a car on a hot day

Where and when to do it

If the only time you can wash your car is on a warm day, try to find somewhere in the shade to do it in. And if that spot is in the shade first thing in the morning or last thing at night, so much the better. If possible, you want to be doing it out of direct sunlight at the coolest possible time of day.

car washing in hot weather
If you can, wash your car at the beginning or end of the day when it’s cooler (Picture iStock/wsfurlan)

Get your kit together

The sun won’t stop shining just because you’ve forgotten part of your car cleaning kit. Before you start washing your car, get everything you need ready. This will include two buckets of warm water. One will contain shampoo, the second is for rinsing your washing cloth. It should also include any product you might want to use and a drying cloth such as a chamois or equivalent. If you’re using either a hosepipe or power washer, get these ready too. To keep your car sparkling, check out cleaning products at the Green Flag Shop.

Jet wash first

If you have a jet wash, spray the whole car. This will blast any dust, grit and loose dirt off. Skip this step and get straight to it with your sponge or wash mitt and you’ll simply be rubbing all this abrasive stuff against your car’s delicate paintwork. If your car has been waxed at some point in the recent past, dirt should lift off more easily. Wax will also help more of the water form into beads and run off your paintwork before it has time to dry on.

Consider your product

Of course, you should never use washing up liquid to clean a car with. And if you’re washing a car in the sun, the better the quality of the shampoo, the easier the job will probably be. You can now buy shampoos that claim they will dry on their own without leaving marks. These will be your ally in hot weather.

Work in small sections

Start working from the top downwards. First of all, wash the roof with the shampoo. Then rinse it. Then follow the procedure on the bonnet, the tailgate, front wings (one at a time), each of the doors, then rear doors and finally rear three quarter panels. You’re essentially working your way around the car, one panel at a time.

Drying is important

Chances are, particularly if you live in a hard water area, there will be marks left on your car’s bodywork after the rinsing stage. These spots will be from the impurities in the water. Some shampoos are designed to prevent this happening without you drying the car. But even if you’re using one of these products, it’s advisable to dry the car. Using a special microfibre drying cloth will make your life a lot easier.

Is waxing a good idea?

As we’ve seen, wax can help with car washing in hot weather. However, applying it in hot sun probably isn’t such a good idea. Car detailing experts say that putting wax onto bodywork that’s baking in the sun can cause the wax to dry too quickly, making it difficult to rub into the paintwork.

2 comments on “Car washing in hot weather: our dos and don’ts for the best results

  1. Chris Lea 30/03/2021 3:51 PM

    Very helpful and informative – thanks

  2. Tanya 13/07/2023 1:47 PM

    Thank you for this advice which has answered my what was dilemma.

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