Trigger VFD (exhaust fan) with outside temperature threshold

I have a whole house exhaust fan setup with a RF dimming module with 0-10 V control. I would like to use this a supplement to my AC on hotter days.

Is there a way to trigger the fan when the outside temp rises above a pre-determined threshold? My preference is to use temp data from weather.com (or some other weather site) rather than a temperature sensor; I think it would be more reliable. Once triggered, I would want the fan to stay on until a pre-determined time in the evening.

I have Ecobee 4 thermostats which I hadn't planned to integrate with RR2 (if that is even possible).

Is there any cheap or free 3rd party software options for this? Any other creative possibilities?

Thanks,
cc

You'll need a third party system for this. Homeseer is mentioned many times here on the forum and is available to the homeowner. You could use a Control4 CA1 to make this happen as well, but requires a dealer for programming and install.

Another 3rd party option is Hubitat. It's cheaper and in many ways less complex than a Homeseer setup. Hubitat (and other 3rd parties) integrate via Telnet. I couldn't see in the Lutron Integration manual if the 0-10v device works the same/has the same commands as a dimmer. If it does - then you are good to go in Hubitat. If not, the Hubitat team is pretty good at responding to requests. One of the founders uses RadioRA 2 in his house.

There are multiple weather sources available in Hubitat. One issue for getting info from weather.com is licensing. These providers all want to be paid to use their data in 3rd party applications.

If you want to use the Ecobee to drive events in your Lutron system Hubitat is a good option for that too as there are a couple Ecobee apps for Hubitat.