Garmin Edge 500 in cold weather
 

Has anybody used Garmin Edge series cyclocomputers in cold weather?

First, does it give accurate temperature readings? My Garmin Edge 500 seems to read consistently high in cold weather i.e., when my ride tonight ended it was 10-13 °F according to several local weather stations, but the Garmin read 17°F. It was dark out, so sunshine was not the cause. Perhaps the unit itself generates a small amount of heat whilst operating?

Second, the specs on the Garmin say that its operating conditions are down to 5 °F. More than likely, I'll be riding at temperatures below that some time in the next month. I am assuming that below 5°F, the altimeter may give faulty readings, but apart from that, has anybody had any other problems?

Haven't tried the 500 at temps that low, but battery run-time will be significantly less, perhaps 50-70% of what it is at 20C. The battery in the cadence/wheel sensor will be affected similarly. Also, the display contrast will change and could get difficult to read, and the display response will be slower. It's possible other things could get wacky, like oscillator frequencies getting out of range and affecting the unit's ability to receive satellites, cause ANT+ to not work, etc.. Rubber button covers/diaphragms might get brittle and crack if you go low enough. If they say it's good down to 5F, I'd probably not worry about trying it down to -5F or so... Of course you could put it in an inside pocket where it can still receive satellites and record your ride data, if not be readily accessible while riding.

At -10F to -20F the display is slow. Seconds don't update quickly. I don't pay attention to any thermometer readings because my winter ride screen is limited to speed, time and heart rate. I don't care much about the rest of it and my cadence unit is on my road bike. My headlight will sometimes cause problems with my Garmin. They are separated as much as I can get them so it's just on the edge of a problem with my speed being whacked occasionally but in general it still works at those temps. Below -20F the screen refresh is stupid slow and battery life plummets. At -30F I don't bother taking it (or for that matter, riding very often but it has happened... :) )