This is so easy to do and works 100% with no installtion required.
And the best part..... Cheap
Place an outdoor sending unit in your service wet bay, Utility Compartment and montor the temp from inside. It is so nice to know the utility compartment temp during cold freezing weather. I have two units: One for the park pedestal or outdoor shade area and the other in the service compartment.
Indoor / Outdoor wireless temp gauges.
I know everyone has seen these.
There are so many, Wal*Mart, Radio Shack, Target, etc etc
outdoor_temperature_gauges : Target Search Results