Satellite Radiation API
Real-time Solar Irradiance From Multiple Satellites
Solar radiation data from NASA GOES satellites has not been integrated yet, so data is currently
unavailable for North America.
Data Sources
| Provider | Satellite | Region | Spatial Resolution | Temporal Resolution | Update frequency | Delay | Archive since |
|---|---|---|---|---|---|---|---|
| DWD | EUMETSAT MTG | Europe, Africa | 0.025° (~ 2.5km) | 10 minutely | Every 10 minutes | 20 Minutes | Feb. 2026 |
| EUMETSAT LSA SAF | MSG | Europe, Africa, South America (only land) | 0.05° (~ 5km) | 15 minutely | Every Hour | 2 Hours | 2025 |
| IODC | Europe, Africa, India (only land) | 0.05° (~ 5km) | 15 minutely | Every Hour | 2 Hours | 2025 | |
| EUMETSAT CM SAF SARAH3 | MSG | Europe, Africa, South America | 0.05° (~ 5km) | 30 minutely | Every Hour | 2 Days | 1983 |
| JMA JAXA | Himawari-9 | India, Asia, Australia, New Zealand | 0.05° (~ 5km) | 10 minutely | Every 10 minutes | 30 Minutes | 2015 |
| EUMETSAT MTG | Europe, Africa | 0.05° (~ 5km) | 10 minutely | Every 10 minutes | 30 Minutes | 2025 | |
| NASA (not yet available) | GOES-East | North & South America | 0.05° (~ 5km) | N/A | N/A | N/A | N/A |
| GOES-West | Pacific Ocean & Alaska | N/A | N/A | N/A | N/A | N/A |
API Documentation
The Satellite Radiation API integrate solar radiation data from various satellite datasets into a single consistent endpoint. Different geostationary satellites are used to provide global coverage.
- Himawari direct and diffuse radiation JMA JAXA provides only shortwave radiation data and does not offer direct or diffuse solar radiation. Open-Meteo applies the separation model from Razo, Müller Witwer to calculate direct radiation from shortwave solar radiation.
- Clear-Sky solar shortwave radiation is only available for DWD satellite shortwave radiation data.
- Instantaneous Values Correction: All satellites provide data as instantaneous values. However, a full Earth scan takes approximately 10–15 minutes. As a result, the top and bottom of each scan have a significant time difference. To ensure comparability with data sources like weather models, OpenMeteo corrects for these scan time differences and derives backward-averaged values.
- Different temporal resolutions: Data is available in 10, 15 or 30–minutely steps. For compatibility, the API returns 1–hourly data. If you want to access the underlying time resolution, make sure to set "Temporal resolution for hourly data" to "native".
Hourly Parameter Definition
The parameter &hourly= accepts the following values. All data is provided in W/m². Solar radiation parameters are available as either instantaneous values or backward averages over the past hour. If you select 10/15/30-minute data, the backward averages will use the same 10/15/30-minute intervals.
| Variable | Valid time | Description |
|---|---|---|
| shortwave_radiation | Preceding hour mean | Shortwave solar radiation is the average incoming solar radiation over the preceding hour at the surface. It corresponds to the total global horizontal irradiance (GHI), defined as the sum of direct and diffuse solar radiation. It accounts for atmospheric effects including clouds and aerosols. |
| diffuse_radiation | Preceding hour mean | Diffuse solar radiation is the average refracted and scattered component of solar radiation reaching the surface over the preceding hour. It excludes the direct solar beam and results from interactions of sunlight with atmospheric molecules, aerosols, and clouds. |
| direct_radiation | Preceding hour mean | Direct solar radiation is the average solar radiation over the preceding hour on a horizontal surface that comes straight from the sun. It excludes any scattered or reflected light and represents the unaltered solar beam reaching the surface. |
| direct_normal_irradiance | Preceding hour mean | Direct normal irradiance (DNI) is the average direct solar radiation over the preceding hour measured on a surface perpendicular to the sun’s rays. “Perpendicular” means the surface always faces the sun directly, as if mounted on a solar tracker, capturing the maximum direct solar beam without scattering. |
| global_tilted_irradiance | Preceding hour mean | Total radiation received on a tilted pane as average of the preceding hour. The calculation is assuming a fixed albedo of 20% and in isotropic sky. Please specify tilt and azimuth parameter. Tilt ranges from 0° to 90° and is typically around 45°. Azimuth should be close to 0° (0° south, -90° east, 90° west, ±180 north). If azimuth is set to "nan", the calculation assumes a vertical tracker (east-west). If tilt is set to "nan", it is assumed that the panel has a horizontal tracker (up-down). If both are set to "nan", a bi-axial tracker is assumed. |
| shortwave_radiation_clear_sky | Preceding hour mean | Clear-sky shortwave radiation is the solar radiation reaching the surface in the absence of clouds. Atmospheric effects such as gas absorption, aerosol scattering, and refraction due to air density are included, while cloud particles are excluded. Under perfectly clear conditions, the regular shortwave radiation can be as high as the clear-sky shortwave radiation. |
| terrestrial_radiation | Preceding hour mean | The solar radiation at the top of the atmosphere, unaffected by clouds or aerosols. It is purely calculated using the solar position factor multiplied by the solar constant of 1367.7 W/m². This differs from clear sky radiation, which accounts for aerosols but not clouds. |
| *_instant | Instant | All solar radiation parameters can be expressed as instantaneous values by accounting for the solar zenith angle at a specific moment. Instantaneous values are useful for direct comparison with local measurements. However, for energy calculations or model evaluations, backward-averaged (preceding hour) data is preferred. By default, the Open-Meteo API provides backward-averaged solar radiation to simplify energy calculations. |