Does rain make windows look dirty?

Have you ever wondered if rain makes windows dirty? This is a common question because it can seem like it was a waste of time to get windows cleaned if it rains right afterwards. Or possibly you’re wondering whether to cancel your booking because it’s about to rain.

The answer to the question is sometimes yes and sometimes no. It all depends on whether the windows have much dirt on them when it rains. When rain falls on a very dirty window, it moves the dirt around and often leaves them looking worse. However when clean windows get rained on, they still look good afterwards.

There is even a middle ground answer. If rain continued to fall on windows regularly after they’ve been cleaned, they would probably stay looking good for longer, because the dirt would get washed away before it had an opportunity to build up and require manual removal.

Another thing to consider is the angle of the glass, because although rain will wash some dirt off vertical windows quite well, it does this with less efficiency the less vertical the window is. This is also made worse by the fact that dirt builds up much more quickly on windows that aren’t vertical.

The best example of this can be seen on car windows. Have you ever noticed that the back window of a car is usually dirtier than the side windows? This is because the back windows is sloping but the side windows are nice and vertical.

Another thing to consider is that rain water has been naturally distilled and doesn’t contain all the minerals tap water contains, which leave marks behind on glass.

However there are a couple of less common scenarios in which rain will make clean glass dirtier. Firstly, if the rain is very heavy it may cause mud to splash up from the ground, or from window sills or tracks if they are very dirty. Secondly, if it happens to be very windy when it’s raining, then debris could stick to the windows while they’re still wet.

I hope you’ve found this information helpful. Below is a video that very briefly explains some of the same information.