As was mentioned, it could just be the LCD. Having used a variety of electronics at low temperatures, I do know that batteries sometimes don't perform well when it's cold. Chemical reaction rates are altered by temperature changes. Lithium batteries are known to function better at lower temperatures than alkaline. Some devices are just more sensitive than others when it comes to voltage loss or fluctuations.

My cycle computer functions well at low temps, but my rear light doesn't. Also, ironically, I own an outdoor electronic thermometer which is rated for -40f, but it stops performing well around 20f if it has alkaline batteries in it.

If you own a voltmeter ( don't we all? ) check the battery when it's cold and compare to the cycle computer manufacturer's specs.