GHI | Global horizontal irradiation | kWh/m^{2} |
Average annual, monthly or daily sum of global horizontal irradiation. |

DIF | Diffuse horizontal irradiation | Average yearly, monthly or daily sum of diffuse horizontal irradiation. | |

DNI | Direct normal irradiation | kWh/m^{2} |
Average yearly, monthly or daily sum of direct normal irradiation. |

GTI | Global tilted irradiation | kWh/m^{2} |
Average annual, monthly or daily sum of global horizontal irradiation. |

TEMP | Air temperature at 2 meters | °C / °F | Average yearly, monthly and daily air temperature at 2 m above ground. |

PVOUT | PV cSi yield | kWh | Yearly and monthly average values of photovoltaic electricity (AC) delivered by the total installed capacity of a PV system. |

WS | Wind speed m/s at 10 m above ground | m/s | Average yearly, monthly and daily wind speed at 10 m above ground. |

RH | Relative humidity at 2m above ground | % | Average yearly or monthly relative humidity at 2 m above ground. |

PWAT | Precipitable water | kg/m^{2} |
Precipitable water is the depth of water vapour in a column of the atmosphere, if all the water in that column were precipitated as rain. It indicates the amount of moisture above ground. |

PREC | Precipitation (rainfall) | mm | Average yearly and monthly sums of precipitation. |

SNOWD | Snow days | days | Snow days are calculated as days with snow water depth equivalent to or higher than 5 mm. |

ALB | Surface albedo | Fraction of solar irradiance reflected by surface. Ratio of upwelling to downwelling (GHI) radiative fluxes at the surface. | |

CDD | Cooling degree days | degree days | Quantifies energy demand needed to cool a building. "Cooling degree days" are a measure of how much (in degrees), and for how long (in days), outside air temperature was higher than a specific base daily average temperature (18°C). Yearly and monthly values are aggregated from daily values. |

HDD | Heating degree days | degree days | Quantifies energy demand needed to heat a building. "Heating degree days" are a measure of how much (in degrees), and for how long (in days), outside air temperature was lower than a specific base daily average temperature (18°C). Yearly and monthly values are aggregated from daily values. |

ELE | Elevation | ||

SLO | Slope | ||

AZIM | Azimuth | ||

POPUL | Population density | ||

LANDC | Land cover | ||

D2G | Ratio of diffuse to global irradiation | Ratio of diffuse horizontal irradiation and global horizontal irradiation (DIF/GHI). | |

OPTA | Optimum tilt of PV modules | ||

TLEO | Lowest expected operating temperature | °C / °F | Mean of annual extreme low temperatures according to IEC 62738. |

Horizon, Sunpath, Day lenght, Solar zenith angle |

Spatial resolution | Data parameters |
---|---|

A9 arc-seconds, approx. 250m x 250m 30 arc-seconds, approx. 1 km x 1 km 2 arc-minutes, approx. 4 km x 4 km 3 arc-seconds, approx. 90m x 90m |
GHI, DIF, DNI PVOUT, GTI, TEMP, ALBEDO, HDD, CDD WS, WD, RH, PWAT, PRECIP, SNOWD Elevation, Slope, Azimuth |

Spatial resolution | Data parameters |
---|---|

2 arc-minutes, approx. 4 km x 4km 30 arc-seconds, approx. 1 km x 1 km 9 arc-seconds, approx. 90m x 90m |
GHI, DNI, PWAT, SNOW_DAYS TEMP PVOUT, Horizon |

Time representation of various parameters depends on the input sources and models behind them. With few exceptions, it spans from the 1990s/2000s to the last year. Depending on the region, the long-term averages are calculated for a period from 1994/1999/2005/2007/2018 to 2022. Please, refer to the map above for the specific start year.

The long-term averages of the other meteorological parameters are calculated for a period 1994-2022 globally.Ground albedo data represents the long-term average for a period 2006-2015.