To maximize the effectiveness of washing your car by hand, does the time of day matter? The short answer is yes, especially during summer months. Several factors can make it difficult to make a wash effective including heat, sunlight, weather, and a few other factors.

In this blog, I’ll share what I’ve found to be the best time and temperature to wash your vehicle, why these factors can be important, and a few things to keep in mind.

Early mornings are usually the best time of day to wash your car

Any time in the early mornings are usually a safe bet according to many detailers I’ve spoken to over the years. It really comes down to the amount of sunlight and heat that you are experiencing. Late afternoons are a close second if you can squeeze it from 5:00pm to sundown.

There are are a couple of factors like temperature and precipitation to keep in mind as well.

Ideal temperatures for washing your car

When it comes to weather and temps, A cloudy day in the 70 to 80 degree Fahrenheit range is just about perfect. The sun can cause problems as detailed in the next section, but extremely cold weather can as well. In this case, around 3:30pm to 4:00pm from my experience is usually the warmest part of the day, but it depends on weather patterns.

However, 70-80 degrees Fahrenheit may not be practical depending on where you live (where it may always be either too hot or too cold). The good news is there are a few tricks for working around it.

Washing a Vehicle in Hot Weather

Especially in the summer months, you want to avoid washing your car in direct sunlight if you can help it. The reason being that soap can easily dry before you have a chance to rise it off, leaving water spots and film behind. If you must wash your vehicle during the hottest part of the day (usually between 1:00 to 5:00pm where I live), find a shady area free of debris, like a carport or shelter.

If you are washing during a hot day, make sure you begin by rinsing the car with water before starting to cool it down. My truck gets insanely hot when it’s above 80 degrees, so I always go slow and make sure the surface I am applying soap to is still wet.

Some clear coats can get damaged by water if the surface is too hot, causing your paint to lack the shine and luster that it once did. Early mornings are again the coolest part of the day, so you should be fine as long as you don’t wait too long.

Quick Tip: After you’ve done a good job washing, don’t take off for a quick air dry! This is a surefire way to leave water marks.

Washing a Vehicle in Cold Weather

Washing your car in the winter months is brutal if you are a hand washer (like myself), but actually a pretty good idea as long as temperatures aren’t below freezing (32 degrees Fahrenheit).

If you try to wash your car when temps are below freezing, water will obviously freeze on contact, and can even crack your windshield (especially if the inside is warmer) Never, ever use hot water to wash or de-ice a car – it’s a great way to crack a windshield.

Some suggest washing your vehicle more frequently during snowier months, because of the salt and brine mixture used for de-icing that your vehicle accumulates. If left untreated, it will lead to rusting out over time, especially in more tropical or humid climates on the east coast of the United States.

It’s also a good idea to pay extra for the underbody carwash if you don’t have a pressure washer to remove salt and debris from under your vehicle.

4 Do’s and don’t – Tips for washing your car outside

Do: Wash your car in sections during hot days

Even in the shade, I’ve found it much easier to wash in sections to ensure I remove the soap as quickly as possible. In other words, keep your wash bucket and hose nearby at all times! I usually keep a sponge in one hand, and the hose in the other as I make my way around the vehicle.

Do: Wash your car after snow, rain, or pollen

One misconception I’ve heard (and used to believe), is that rain is just a natural way to wash dirt off of your vehicle, but that’s not always the case. The chemicals and contaminants left behind after a rainstorm or snowstorm can damage paint, and lead to rusting.

Even if your car gets rained on in your driveway, acid rain can be a problem (depending on where you live), causing swirls and dried pollutants in the surface. Acid rain caused by pollutants are pretty common in the Northeastern US, as well as industrialized areas.

If you live in an area where there is high pollen live I do, it’s also a good idea to wash your car during pollen season. Pollen is actually slightly abrasive, and can lead to fading or scratching over time.

Don’t: Wash in direct sunlight

If you can help it, try to wash your vehicle in a shady area instead of direct sunlight to avoid soap sticking to the surface, leaving behind streaking and water spots.

It’s sometimes hard to tell soap has dried until the next time you wash your car, and you spray it with water, only to notice some suds left behind – I’ve been there. Doing the best you can to dry your car quickly with a soft towel is equally as important to avoid dried water spots from appearing.

Don’t: Wash your car at night

Once the sun goes down, it’s can be difficult to get your car completely dry, which a be a problem. A damp vehicle surface can lead to corrosion since you don’t have the benefit of sunlight to aid in this process. From my own experience living in North Carolina, washing or wiping down my truck at night (especially in the summer) is a bad idea, because of gnats, moths, and other insects that can stick to the surface. It’s also nearly impossible to not miss a spot, even if you have floodlights.

Conclusion

Hopefully, this gives you a better idea of when to go about washing your car, and a few things to be aware of to get the most out of your time spent. If you have any other questions, comments, or additional advice, leave a comment below.