Thanks Ray. To give you an example for the last few days watering adjustment has been around 110-120% with mild summer weather. Today its reached 200% on a very hot day, so it does make a significant difference. Is it possible a workaround would be to write a program which called the weather service for the Evaporation adjustment, then calculated the average and adjusted the watering percentage ?
For what is worth i have just bought my second Open Sprinkler, its a great product.