Just remember temp is always going to be affected by placement--sun, wind, if it's near something that might affect it (warm/cold wall), etc. Or at least I assume it is. There's certainly going to be variation. No clue if that's enough to explain it. Personally sometimes I'd like to see the temp _inside_ the car, too. So I can compare inside vs outside or something. Seeing what the thermostat's set to doesn't help, especially when some of us (at least me? hehe) don't use it very often...

 

I've never seen mine go below 38.

 

I can't complain with mine, always within 1-2 F of the temperature from other, accurate sources, within error of conversion, but then lowest I ever had so far was about +10F, maybe bellow zero is less accurate. And please don't tease me with this conversion to metric, is US the only country in the world still using ancient system of feet and gallons (and make sure you know which one), behind Afghanistan , Botswana etc? BTW, NYS uses 8 1/8%, 8 2/8% and 8 3/8% on its official tax forms for taqx rates, instead of decimal way like 8.375% etc. and then provide table look up at the bottom for your convenience, so you can actually calculate it in some simple way, very strange sometimes.