You Will Need
This looks simple but I created the Ruby Gem for this so you don't have to do the hard work, you could do it all in one script.
One you have Ruby installed you can get the example script from GitHub
Create a Number item with a binding to call the Ruby script and use the output to update your Number item, obviously change the "OpenHABAlertMe.rb to whatever you called your script.
Number Temperature_Hive "Temperature [%.1f °C]" <temperature> (Living) {exec="<[ruby C:/Tools/Scripts/OpenHABAlertMe.rb:60000:REGEX((.*?))]"}
Here is the event bus update
And the corresponding UI