This can at times be important, and know that ambient temperature matters…
You actually don’t need an app installed for this, as most HTC phones got a “hidden” Info menu where you can see battery temperature etc.
To access this you enter
*#*#4636#*#*
in your dialer. Then select Battery information, where you see battery temperature. Which is the temperature value you can get. I’ve left out the last * on the first screen shot.
Or, you can install an app made for this. There’s two different ones that I use.
Hwmonitor is just the basic info about battery etc. Not a lot of more hardware information.
And then you’ve got the slightly more featured-filled CPU-Z which gives you hardware information as well.