Outdoor temperature that works with vcrx contact closure

I am working on a project and have hit a snag. I need a device that can sense an outdoor temperature and using the vcrx contact, close the circuit and given another temperature open the contact. Has anyone ever seen something that can do this? Basically the VCRX will tell a CCO to activate given a temperature. The CCO is controlling kickspace heaters. The kickspace heaters are a 2nd system on top of radiant heat. The client is using them to boost the system to get the house up to temp faster than the radiant heat can. The client wants the toe kick heaters to kick on automatically given a temperature outside and turn off given a temperature inside. Any help would be great!

You'd likely need a separate, 3rd party automation system to do this. One that would use any number of other temp sensors to do this.

I'd question the logic of outside on, inside off. You'd likely need more nuanced integration than that. Perhaps treating it like 'emergency heat' in a thermostat system that's controlling his radiant setup. You really want to avoid 'reinventing the wheel' when it comes to HVAC systems.