This functions returns a data.frame with weather data from the NASA POWER database. It has the date, incoming solar radiation (srad, kJ m-2 day-1), minimum temperature (tmin, degrees C) and maximum temperature (tmax, degrees C), vapor pressure (vapr, Pa), precipitation (prec, mm), and windspeed (wind, m/s)
The data are from 1983-01-01 to 2016-12-31
Missing values for radiation (Jan to June 1983 and ...) and a few inbetween were replaced by the long term averages.
There are no precipitation values before 1997-01-01. Missing values for precipitaion after that date were estimated as the long term average (i.e., not a particularly good method).
The data are at 1 degree spatial resolution. That is, they are the average for a large grid cell.
These are estimates. They can give a good general impression, but they are not ground observations.
Data are downloaded as-needed by tile. By default to folder called "power" in your working directory.