How does a car’s outside thermometer work?

I’m curious, how does a car’s outside thermometer work? Shouldn’t the heat of the engine or wind chill make the reading inaccurate?

Those are great questions! Interestingly, cars use a thermistor, not a thermometer, to generate temperature readings.
Unlike thermometers, thermistors don’t use a liquid like mercury. They read the temperature by measuring the change in electric current as a result of heat added or taken away. In general, thermistors are small, cheap, and accurate, making them incredibly convenient in automobiles.
Thermistors are strategically placed to prevent the engine’s temperature from influencing the reading and are often found behind the grill but in front of the radiator or in mirror housings or fenders. Additionally, only living creatures experience wind chill, so the thermistor does not have to be shielded from wind to get an accurate reading.
While engine heat and wind won’t skew the temperature reading, reradiated heat from the road can cause inaccurate readings, which is why your car’s temperature reading may seem abnormally high if you’re parked on hot pavement.
Unfortunately, there is no way to avoid the influence of reradiated heat on the reading, but this should only inflate it by a few degrees—unless it is an incredibly sunny or hot day.
If you want to get an accurate reading on if you’re overpaying for car insurance, download the Jerry app!
Jerry is an insurance comparison app that shops for low prices with over 50 different insurance companies for free. You will get quotes in seconds, can make changes at any time, and if you ever have any questions, agents are just a text away!
Jack Walsh
Answered on Nov 24, 2021

Did this answer help you?

Ask us a question by email and we will respond within a few days.

Have a different question?

You can meet us at our office and discuss the details of your question.
Let Jerry’s experts help you find savings on your car insurance!
No long forms or spam · Get quotes from 40+ carriers
Find insurance savings (100% Free)
rating primary
4.7/5 Rating on App Store

Easiest way to compare and buy car insurance

No long forms
No spam or unwanted phone calls
Quotes from top insurance companies
Find insurance savings — it's 100% free