Why You Should Wait Until It's Cloudy Outside To Clean Your Windows

Cleaning windows is one of those jobs that you probably don't think you need to do – until you actually start doing it. Windows easily collect hard-to-see smudges from dogs and kids pressing their faces against the glass. Dirt and grime that clings to the windows after windy and rainy weather can be difficult to remove. Once you finally clean the windows, you might be surprised how dirty they actually were.

However, most of us put off this job because cleaning windows can be a difficult, time-consuming job. It's also easy to make big mistakes when cleaning windows, which might make you nervous about doing it. One of those potential mistakes is trying to do the work on a warm, sunny day. Although it can seem like cleaning the glass on a sunny day is ideal for removing smudges, this usually isn't the case. When working on a window exposed to the sun, the liquid cleaning solution may evaporate before you have a chance to wipe it off, which can leave streaks and other marks behind. With the glare from the sun on the glass, it can be difficult to see those streaks, meaning you might think the window is clean when it's covered in streaks. So, the big benefit of washing your windows when it's cloudy outside is a streak-free finish.

In addition to cleaning windows without streaks by working on a cloudy day, a few other reasons exist for avoiding washing the glass when the sun is shining. Learn more about reasons to stick to cloudy or shady days when cleaning the glass. Remember, you don't want to pick a rainy day; just pick a cloudy day.

Not only is it hard to clean your windows for a streak-free finish when the sun is shining directly on them, but you also have to work in uncomfortable conditions. Direct sunlight going through a window can increase the temperature inside your house, but it can also heat up the surrounding area. The glass absorbs the sun's radiation and redirects it. Direct rays from the sun can make the glass uncomfortably hot to touch, increasing the challenge of cleaning the windows. Glass can increase in temperature about 35.6 degrees Fahrenheit (2 degrees Celsius) for every 20 minutes of sun exposure with a maximum temperature rise of 50 degrees F (10 degrees C). It can drop about 38.4 degrees F (3.6 degrees C) when going from sun to shade over a 20-minute period. The sun's heat becomes trapped near the window glass, too, making it uncomfortable to work. If temperatures are extremely high along with uncomfortable humidity, you might run the risk of dehydration or even heat exhaustion while cleaning the windows.

If the temperature of the window glass is high, it will slightly expand inside the window frames. Should you spray a cool-temperature cleaning solution onto the heated glass, the temperature difference could cause thermal stress for the glass that eventually leads to cracks or breakage. The heat of direct sunlight on the window glass can cause the surface to feel stickier, too. The glass has no residual moisture on the surface because any moisture dries quickly, leaving it difficult to move a rag across the heated glass surface.

Sometimes, chores can't wait for the perfect time. You might need to clean your windows even when the sun is shining on the glass. Are there ways you can do this work while minimizing the risks of streaks?

Avoid cleaning the glass when the sun is shining directly on the windows. Try working in the early morning or late evening when the sun is lower in the sky. You can also work in small sections on a pane of glass, starting at the top of the window and moving downward. This should reduce the risk of streaks because you should be able to dry the small section of glass before the cleaning solution evaporates. To avoid the warmest weather on a sunny day, consider cleaning the glass in spring and autumn instead of in summer. If trees or an overhanging roof line place some temporary shade on windows during the day, try to schedule your cleaning during these times when the glass should be cooler.

When cleaning window glass on a sunny day, try completely drenching the section of window where you're working. Adding extra moisture can reduce the temperature of the glass to slow evaporation, while the extra water gives you more time to wipe the liquid away before it completely evaporates. Consider adding a gliding agent to your cleaning solution, which keeps the glass wetter in the direct sun.