If you're lucky enough to live in a place with warm weather year-round, you may not know how hot it actually has to be to crack car windows. The answer may surprise you - it doesn't have to be that hot at all! In fact, cracking car windows is more common in cooler weather than you might think.
When the temperature outside is around 20 degrees Fahrenheit (-6.7 degrees Celsius), the glass in your car's windows will start to contract. This contraction causes stress on the window, and if there are any weak spots or cracks already present, they will likely worsen and cause the window to shatter. So if you live in a cold climate, be extra careful when driving with your windows down - even a small pebble hitting your windshield could cause it to crack!
Of course, heat can also cause car windows to crack. If the temperature inside your car gets too high, the glass will expand and again put stress on any weak spots. This can happen even more easily than with cold temperatures, as we tend to crank up our heaters in our cars without giving it much thought. If you're going to be driving in hot weather, try to keep your car as cool as possible - open the windows for ventilation and park in shady areas whenever possible.
Ultimately, whether it's due to cold or heat, any kind of extreme temperature change can cause your car windows to crack. So next time you're out driving in either very hot or very cold weather, take extra care of your windshield and make sure there are no cracks or weak spots that could give way under pressure!