How GoodDayTo judges car washing weather
The frustrating part of washing a car is not the weather while you are washing it; it is rain arriving soon afterwards. GoodDayTo checks the following six continuous forecast hours so a dry start followed by a likely shower does not get treated as an ideal result.
- Current precipitation
- Rain probability in the following six hours
- Wind speed
- Temperature
- Drying conditions
🌞 Make the most of the good window
- Choose a period with several dry hours after the wash when possible.
- Avoid washing a very hot body panel in intense sun because water can dry too quickly and leave marks.
- Strong wind can blow dust and debris onto freshly cleaned paintwork.
When a good car-washing score is most useful
For washing a car outdoors, the best weather is usually dry, not too windy and unlikely to rain soon afterwards. GoodDayTo penalises rain risk strongly because a wash immediately followed by a shower is frustrating and can leave fresh spotting. It also reduces the score as wind rises because wind can carry dust, leaves and spray across the vehicle while you work.
A WAIT result can be worth following when the forecast shows a drier block later the same day. In hot sunshine, working panel by panel and avoiding water drying instantly on the paint can help reduce water marks even when the overall weather score is good.
How the six-hour outlook changes the verdict
GoodDayTo keeps the first screen simple, but the rule underneath is deliberately clear. If the next six continuous hours contain at least 0.5 mm of forecast rain or a rain probability of 70% or more, an otherwise ideal start is capped at NOT TODAY. A smaller signal—at least 0.1 mm or a 40% rain probability—caps it at WAIT. A dry six-hour outlook does not guarantee a spotless car; it simply removes that particular reason to hold back.
What the car-washing score cannot know
GoodDayTo does not measure local pollen, construction dust, water hardness, restrictions on outdoor water use or whether your driveway is shaded. It also cannot predict every brief local shower. The score is designed to answer “is the weather broadly worth washing in?” rather than judge detailing technique, paint condition or local water rules.
What the score means
GO means the weather signals we can measure look favourable. WAIT means conditions are mixed and a better hour may be nearby. NOT TODAY means the forecast currently contains enough unfavourable signals that this activity is unlikely to be a good weather choice. These are planning recommendations, not safety clearances.
Car-washing example: look beyond the wash itself
A dry hour can still be a poor choice if rain is likely soon after you finish. GoodDayTo therefore checks the next six continuous forecast hours instead of only the moment you start washing. Strong sun, shade, water quality, local water restrictions and the products you use can also affect the result on the paintwork, and those details are outside the weather model.
Frequently asked questions
Why can a dry hour still get a WAIT result?
Because GoodDayTo looks beyond the current minute. A dry hour can still be a poor choice if showers are likely soon, wind is strong or the surrounding hours do not give you enough time to wash and dry the car.
Is strong sunshine always good for washing a car?
No. Very hot bodywork can make water and cleaning products dry too quickly, which can leave marks. Mild, dry weather with manageable wind is often easier to work in.
Does wind matter when washing a car?
Yes. Strong wind can blow dust, leaves and grit onto wet paint and can make spraying or drying more awkward, so windy conditions reduce the score.
Does the score consider whether it will rain after I finish?
Yes. It checks the next six continuous forecast hours. A likely rain signal can cap the result at NOT TODAY, while a smaller signal can cap it at WAIT. It cannot guarantee that a very local shower will not develop.
What does a GO car-wash result actually mean?
It means the measured forecast looks favourable for washing outside. It does not assess local water restrictions, shade, paint temperature, water quality or the products you are using.