I'm working on a project outside of the US, therefore I am using the international version of the WaterSense Water Budget Tool downloaded from the USGBC website.
In order to calculate the watering demand for the site, I need to input monthly rainfall (mm) and monthly ETo(mm).
I calculated the first one by averaging out the daily values of rainfall using a set of 10 years data (that is what I have available from the weather station). For the Monthly ETo I have downloaded the calculator from the website below: http://www.fao.org/land-water/databases-and-software/eto-calculator/en/ but I cannot find anywhere in the manual a reference on the type of data that are required for performing the ETo calculation. One option of the data input is the average temperature and wind speed. Also I would like to know how many years of data are required for the input data, both for the Monthly Rainfall and the Monthly ETo.