The sun temperature sensor is normally a temperature only sensor on top of the pole, but FreeWX-Wi has problems with this sensor when the temperature dips below 0 Celsius. So for the winter I changed it to a temperature & humidity and placed it on the pole. This sensor doesn't catch as much sun light in the morning and evenings in the summer months.
Hope an update for FreeWX-Wi will come out and fix this, but there hasn't been one yet.