Skip the auto shop - Our mechanics make house calls

Q: Can Cold Weather Crack Your Car Windows or Windshield?

asked by on

Can cold weather crack your car windows or windshield?

A: When considering if cold weather can crack ...

When considering if cold weather can crack your windows or windshield, it is important to first note that glass windows are under tension.

As with any material, glass is subject to stress through expansion, and compression or contraction with changes in temperature. If the windshield or rear windows are completely covered in ice, then it is possible for them to crack when heating them either with the vehicle’s main heater, or using the electric defrost mode. This also applies to the side windows, but, more commonly, it affects the rear window or windshield due to the direct application of heat. In fact cracking is also possible if the temperature that the glass is exposed to goes through extremes, even without being coated with ice.

Automotive windows are made using tempered glass for the side and rear window, and laminated glass for the windshield. The tempered glass is a single pane which is designed through a process which repeatedly heats and cools the glass during its production and gives it strength to withstand the normal forces that are exerted while driving. The windows are subject to flex as the body is bouncing down the road and shifting when the vehicle goes through turns. This strong glass is designed to shatter into small pieces in the event of an impact. As i mentioned before, it is under tension, but very sturdy while at the same time susceptible to shatter under the right conditions.

Pressure over a large area generally will be deflected by the glass and it will not shatter. However, a fine point of energy applied will generally cause the window to shatter into thousands of pieces. That being the case, it’s possible for temperature and stress to contribute to the window shattering. In fact, this is most common on rear glass panels in vans and large SUV’s. I have seen cases of these windows actually exploding when cold or frozen and the rear electric heater element is turned on. The rapid heating of the window combined with the stress or flex of the body can cause it to shatter violently in some cases.

When it comes to windshields, they are laminated. This means that two pieces of glass are bonded together with a plastic layer in between. This strengthens the glass and while it does not make it crack proof, it is by design basically shatter proof. The windshield can be cracked slightly or appear to be shattered but because of the lamination, it will remain in one piece. This is for driver and occupant safety.

Whether it’s for a windshield or a window, you should never attempt to de-ice or defrost with hot water, as the sudden heat stress can cause window cracking.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Change direction of wipers

This would require modifying the windshield wiper motor which could be costly. If it is an issue of the quality of the job they do, I would suggest purchasing better quality wiper blades.

Q: Can a Car Battery Freeze?

A new or nearly new car battery in most of today’s vehicles is fully charged if the voltage is at about 12.6 volts. When a battery starts to age the voltage that it can store will start to be less...

Q: Deafening sound from something blowing out through sunroof

Hi there, and thank you for asking about the event that happened with your 2013 Lexus RX450h. Although certainly frightening, this is likely a truly rare event. Most automotive glass has multiple layers of glass, joined by a plastic layer...

Related articles

P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.