I can’t type out a full solution now, but here are some hints:
To convert a hex string to ASCII, there’s no Jinja2 or HA templating built-in ways. Luckily, Petro has typed up the algorithm.
Once you have that, you can use a regex.
I just quickly made a regex in Python (experiment with this in your template editor):
import re
h = "0x43656e746967726164653a3336200946616872656e686569743a3936"
s = bytearray.fromhex(h[2:]).decode() # 'Centigrade:36 \tFahrenheit:96'
m = re.search(":(\d+).+?\:(\d+)", s)
m.groups() # ('36', '96')