Jejje
Washing the car on a warm, sunny day feels tempting, but it's actually one of the most reliable ways to get a worse result than necessary. Here's why - and how to manage it if shade isn't available.
Why is sun a problem when washing?
Heat from the sun makes both paint and glass warm - sometimes significantly warmer than the air temperature. When water or cleaning products land on a hot surface, they start to dry in almost immediately. Often before you've had a chance to rinse them off or wipe them dry. The result is water spots, dried-in shampoo residue and, in the worst case, wax products or sealants that cure unevenly and become difficult to buff off.
A hot paint surface also means any abrasive particles in the grime move across a softer, heat-affected surface, slightly increasing the risk of micro-scratches compared with washing on cool paint.
Best times to wash your car
- Early morning or late evening, before or after the sun has had a chance to heat the paint properly.
- Overcast days, which provide even, cool conditions without direct heat.
- In shade under trees, a carport or a garage if possible - this is usually better than just waiting for the right time of day.
- On very warm days, indoor self-service car wash bays are an excellent option.
If you must wash in the sun - how to minimise the damage
Sometimes there's no choice - for example if the car can only be washed at home on a sunny patio. In that case, work quickly and methodically:
- Wash one section at a time instead of the whole car at once - for example one side at a time.
- Rinse off the shampoo immediately after working each section - never leave it sitting while you finish the rest.
- Have a drying towel ready immediately after rinsing so the water never gets a chance to dry on its own.
- Avoid dark-coloured cars in the middle of the day if possible - dark paint absorbs more heat and gets considerably hotter than lighter colours.
Glass is especially sensitive
The windscreen and side windows often get even hotter than the paint in direct sunlight, which means glass cleaner can dry in with streaks as the result. Save glass cleaning for the coolest point in the wash, or do it last when you can work in the car's own shadow.
- Choose morning, evening or overcast weather for the best wash results.
- Wash one section at a time if shade isn't available.
- Rinse off product immediately - never let it dry in the sun.
- Have the drying towel ready immediately after rinsing each section.
- Save glass cleaning for the coolest part of the wash.
Summary
You can wash the car in the sun, but it's not ideal and requires you to work faster and more methodically to avoid water spots and dried-in product. If possible, choose shade, morning or evening instead. If you must wash in the middle of the day, work section by section and have the drying towel ready immediately after each rinse.
