I run this file in a cron job every 5 minutes. It checks the CPU temperature using various sensors (using the 3rd party package lm-sensors) and sends en e-mail to a configurable e-mail address if any one of the temperature exceeds are configurable threshold.

cpu_temp_checker.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
A simple program that sends warnings when disk space on one or more hard
drives has reached a critical level
"""
import re
from subprocess import Popen, PIPE

##############################################################
#CHANGE SETTINGS BELOW
##############################################################
EMAIL_ADDRESS = 'davidgrant@gmail.com'
THRESHOLD = 60
#if SEND_EMAIL=True, email will be sent, else, just stdout
SEND_EMAIL = True
REGEXES = (
    ('CPU temp', "CPU Temperature: *\+([\d\.]+)°C.*",),
#    ('CPU temp', "",),
          )
##############################################################
#DON'T TOUCH ANYTHING BELOW UNLESS YOU KNOW WHAT YOU ARE DOING
##############################################################

RE_OBJS = [(x, re.compile(y)) for x,y in REGEXES]

def main():
    """ Main method """
    msg = []
    output = Popen(['/usr/bin/sensors'], stdout=PIPE).communicate()[0].decode('utf-8')
    lines = output.split('\n')[1:-1]

    errors = []
    for name, regex in RE_OBJS:
        for line in lines:
            match_obj = regex.search(line)
            if match_obj:
                temp = match_obj.group(1)
                if float(temp) > THRESHOLD:
                    errors.append((name, float(temp)))
                break
        else:
            print('Did not find match anywhere')

    if len(errors) == 0:
        return

    # Make an email message
    for name, temp in errors:
        msg.append(name + ", measured= " + str(temp) + ". Exceeds threshold=" + str(THRESHOLD))
    if len(msg) > 0 :
        msg = "\n".join(msg)
        if SEND_EMAIL:
            mail_command = 'echo "%s" |mail -s "[cpu temp high]" %s'
            Popen(mail_command % (msg, EMAIL_ADDRESS), shell=True)
        else:
            print(msg)

if __name__ == "__main__":
    main()