This tutorial by user shows us how to find the temperature of your CPU via command line. Follow the link below for the full instructions.

I’m a new FreeBSD unix user. How do I get the temperature of an Intel or AMD processor (CPU) in FreeBSD using command line option?

You just need to type the following command to see cpu temperature in FreeBSD:
$ sysctl -a | grep temperature
$ sysctl dev.cpu | grep temperature

Sample outputs: ….

Full tutorial: