Garmin offers an accessor called the "Tempe". This is a little gadget that runs off of a coin cell and transmits temperature data to the Instinct (and no doubt anything else that is listening). The Tempe costs about $30 and what I read is that it will run for well over a year on a single battery.
The battery is a CR2032, which is probably the worlds most common coin cell battery.
The story is this. The Tempe transmits a data packet once every minute. Period. It never listens. The packets includes the current temperature as well as the max and min values for the last 24 hours.
Once it is all set up and you get on the trail, you select the screen to view the temperature. It will always say "Temp. not connected". You will have to wait for up to 59 seconds for the Tempe to send data and then it will be displayed. This is less than pleasing and useful to say the least. But if you understand the game, it does work. I usually keep hiking and the next time I check the watch is back to displaying time, so I have to start the game over. And I have to repeat the exercise until I get lucky. Every time the watch times out and returns to showing the usual time display, the temperature data gets cleared.
I would say this is bad (perhaps even stupid?) programming for the Instinct. Perhaps listening all of the time would drain the battery and they are doing the only reasonable thing. But it is wretched and frustrating.
If you have a handheld GPS, pair the Tempe with that and you will be much much happier.
When it arrives, you install the battery and it is ready to go, the trick now is to pair it with the instinct.
It uses the ANT+ wireless protocol, which you may or may not care to learn about. Some smartphones have ANT+ receivers and can work directly with the Tempe.
The range is about 10 meters with line of sight. So they say, I'll do my own testing and report here someday.
Press and hold menu. Press Asc twice to get to Settings. Press GPS once to enter settings. Press Asc 4 times to get to sensors and accessories. Press GPS once to enter sensors and accessories. Press GPS once to "Add New" Press GPS again to "Search All" After a while it should detect the Tempe and offer to add it. (if it doesn't find anything, this is not uncommon, try again) Press GPS again to do so.
Once you have added it, you can revisit "sensors and accessories" and find it in the list. Selecting it by pressing GPS lets you check status and perhaps other information, although my unit shows all those fields as "---".
Note that the watch can also display temperature data that it gets from you cell phone (which in turn comes from some internet weather service somewhere), so don't get confused.
You get to the temperature widget by pressing the lower left button (Asc) repeatedly, or better yet --- I find the fastest way to get to it is to press Menu twice.
Once it is paired, this "face" will look different and will display the current temperature as well as a max and min temperature. Note that it now displays temperature in tenths of degrees (not just whole degrees as the sensor built into the watch).
I am reading that the tempe itself keeps track of max and min, and tracks them over last 24 hours, which is a wonderful improvement over the 4 hour period that the watch uses with its built in sensor. It even means that you could turn the watch off, then in the morning turn it on and once it got data from the tempe you would know what the low overnight temperature was.
Tom's home page / tom@mmto.org