Solar Radiation vVARY

Here is a nice application that displays the instant and the mean values of the most important indices related to the solar irradiance. This accurate measuring tool (portrait orientation, Android 6 or newer) works on the tablets, phones and smartphones that are connected to the Internet. At first, it gets the local coordinates (latitude and longitude) from your device's GPS and then retrieves those parameters from an Internet server. There are five important parameters that show the amount of solar radiation received per square meter:

Shortwave Radiation - GHI - is equal to the total Global Horizontal Irradiation;
Direct Radiation - DIR - is the amount of direct solar radiation on the horizontal plane;
Diffuse Radiation - DIF - is the amount of diffuse solar radiation that come equally from all directions;
Direct Normal Irradiance - DNI - is the amount of direct radiation received on a surface perpendicular to the position of the Sun;
Terrestrial Radiation - TER - is the amount of outgoing longwave radiation emitted by the Earth's surface to space.

The GHI parameter is actually the sum of DIR and DIF. All of these indices are provided for the current day, but there are 7-day forecasts for all indices, both instant and average values.
The sum of all GHI hourly indices can be used to calculate the total energy received by each square meter of your solar panels. This value includes their efficiency and other energy losses that occur during conversion to electricity.

Features:

-- instant display of the solar radiation indices at current location
-- easy calculation for the energy generated by your PV system
-- 7-day forecast for all solar parameters
-- free application
-- no limitations
-- only one permission required (Location)
-- this app keeps the phone's screen ON