I am in central Ohio and wild temperature swings in the spring and fall can be handled easily with my Vera 3 and Vera Plus. Originally, I used PLEG and now I use Reactor. Here is what I do.
Using either the virtual outdoor temperature sensor or weather underground, I watch the outside temperature. If > 65F, I set the mode to cooling. If <60F, I set it to heating. So this runs 24/7 and solves the heat in the middle of the night but cool in the middle of the afternoon without touching the thermostat.
At the same time, I have my heating and cooling setpoints set based on house mode:
Mode Heating Cooling
Home 68 75
Away 65 78
Night 65 72
Vacation 60 89
The house modes are set by watching the 2 iPhones using iPhone Locator. If either or both are home, then Home. If both are more than 0.1 miles but less than 75 miles, set to Away. If both are more than 100 miles, set to Vacation. This is ignored is my Guest virtual switch is on.
Night is set to be on at 9:30 pm Sunday through Friday, 11 pm Saturday. Turned off 5:30 am Monday through Friday, 7 am Saturday , Sunday, or a weekday with the Holiday virtual switch on.