What about the temperature ?

IDK about the 1040 yet, but on previous Edge units the temperature readout is a byproduct of a temp sensor that is integral to the baro sensor.  The baro sensor is temperature sensitive so includes a temp sensor so that it can be corrected.  That temp sensor measures the temperature of the baro sensor, not ambient temp. Since it is inside the Edge with no direct airflow over it, it doesn't measure or respond properly to ambient temp and gets warm when the Edge gets warm. 

Any device on the front of the handlebars is vulnerable to heating directly by the sun and indirectly by radiation from a hot road surface. Put your 1040 in a shady place along with some other temperature measurement devices and see if they agree. My observations indicated that my 1030 would read 3C low on a cloudy day which would similarly reduce the reported temperature in the sun. I've currently got the impression that Garmin haven't applied the offset to the 1040 which means it will read higher.

There’s documentation from Garmin that says it doesn’t use temp for the barometer. 

Regardless, if thermometer doesn’t report the temperature accurately, the device shouldn’t report it.

looigi said:

The baro sensor is temperature sensitive so includes a temp sensor so that it can be corrected.  That temp sensor measures the temperature of the baro sensor, not ambient temp. Since it is inside the Edge with no direct airflow over it, it doesn't measure or respond properly to ambient temp and gets warm when the Edge gets warm. 

It makes sense to measure the temperature for the barometer. 

No one cares about the temperature of the barometer.

People are expecting the reported number to be the ambient temperature.

People keep complaining that the temperature is wrong. 

Why have the device report the wrong temperature temperature?

Is it wrong all of the time or some of the time? I'm waiting to see if it's correct on a very cloudy day when there's no solar radiation to heat up the Edge. The temperature reported by the Edge 1030 was about 3C low under such conditions. Heating in the sunshine is something we have to accept and affects both the Edge and the cyclist.

JRat1 said:

Heating in the sunshine is something we have to accept and affects both the Edge and the cyclist.

One could use a thermometer that isn’t in the sun.

The basic problem is a mismatch between what people expect and what they get.  If that mismatch is common, then, maybe, one shouldn’t provide the information.

JRat1 said:

Is it wrong all of the time or some of the time?

Seems like, if that’s the question, it’s wrong too often. 

I was out riding with my wife this morning, she with a 1030, me with a 1030+, both on out-front mounts. When we stopped at some traffic lights after having been riding for about an hour, we compared the temperature data fields the two units were displaying. Hers showed 4.2°C, mine 8.5°C, and we'd been riding alongside each other in identical conditions. If we were using Fahrenheit for temperatures, the two would have been almost eight degrees apart.

I reckon I'm much better at guessing the temperature than Garmin's temperature sensors are.

Around + 3,5C +4C

I know that also Edge 830 had this issue, and they somehow fix it 

here it was 33 outside

C 

I did another temperature comparison this morning when it predominantly cloudy with a hint of sunshine during the middle part of the ride when the 1040 registered 21C and the 530 and Tempe (with +2C correction) registered 20C.

I also compared the temperatures at the end of my ride with the Davis Vantage Vue weather station in my garden. The numbers were: 1040 = 18C; 530 = 17C, Tempe = 17.61C (very precise!) and the weather station = 17.2C.  On that basis the 1040 might be reading slightly high, but probably no more than 1C.There was no room to fit the Edge 1030 on the handlebars but past experience indicates that it reads about 3C in cold and cloudy conditions. Wrist-mounted Garmins are also vulnerable to solar heating if exposed to the sunshine and will also read high in cold weather if under clothing.

I'm happy to accept that the Edge 1040 suitably accurate when solar heating isn't a factor. Using the Tempe reduces the solar heating problem but, at the moment (latest beta software) Tempe Visualizer won't coexist with the Varia Radar.

Tempe Visualizer is working fine with software 12.15 (it's now showing the same values as on my Edge 530). Here's today's temperatures on what has been a sunny day. The 1040 shows much more variability depending on exposure to sun and cooling by wind. The maximum of 31C was going uphill towards the sun. The Tempe (mounted under the stem and with +2C offset) recorded a maximum of 26C which I think was close to the truth giving the heat being radiated by the tarmac.

At the end of the ride the Tempe was within 1C of the weather station in my garden while the temperature reported by the 1040 was about 3C high.