I saw the above quote on another forum. Anyone able to confirm/deny this? Haven't heard about it before.

HJ

I can confirm as AZ resident and -- until things got 'less comfortable' -- frequent traveler to Mexico. Not GPS, but digital camera display.

Initial experience right after buying first digital camera -- a Nikon -- six or so years ago. Bought expressly for month-long stay @ Monzanillo, Mexico. Hot 'n humid! When happened, thought I got a lemon. But when display later functioned (after indoors awhile), put 2 + 2 together and decided was the heat. Some experimentation later, proved to my satisfaction. Later confirmed researching on internet.

My solution, which has worked OK:

1. I never leave camera outside padded (read: insulated) carry case any longer than necessary.

2. Always been my electronic-device rule, but CLOSELY follow with camera: don't leave in direct sunlight. Likewise, avoid leaving in car (e.g. when A/C isn't runnning). For times when absolutely necessary, have small, dedicated collapsable cooler in Jeep for camera or other small electronics to provide some protection from heat.

3. Not big deal here in AZ, but in Mexico: stuffed couple of small silica gel packets into camera case just to keep humidity at bay.

When first happened, LCD display seemed to recover without permanent impairment.

BTW, can't cite exact temperature first time happened in Mexico, but definitely <110°.

Garmin seem to specify their GPS units operating in temperatures from 5ºF to 158ºF (-15ºC to 70ºC), which just happens to be the operating temperature of Standard TFT and Wide Temp STN

http://americas.kyocera.com/kicc/Lcd/notes/tempconsider.html

So the Garmin should work OK within this temperature range. At very cold temperatures the display will be very sluggish to change taking a couple of seconds for the LCD pixel to switch on and off.

There may be some GPS units that use Standard STN LCDs which may have a problem with the temperature extremes.

CFL Backlight issues would probably be more of a problem for the higher end models. The cheaper wide temperature STN LCDs are generally easier to read in daylight than standard colour TFT (which needs a white coloured backlight i.e. newer LED and CFL).

Of course the user using the GPS may not be operating at 158F.

This effect varies based on the manufacturer and model of the display. Some displays handle heat better than others. In my experience, newer displays handle heat better than older ones.

My car Garmin GPS quits working if I drive with it on the dashboard
in hot weather.

I don't know so much about hot weather, but I can tell you that electronic displays definitely quit at about 30 below.