Collection: Duration of sunshine

Sunshine duration was defined by the World Meteorological Organization (WMO) as the period during which direct solar radiation exceeds 120 W/m² and is measured in hours.

Sunshine duration sensors are primarily used in weather monitoring networks and in holiday resorts to inform tourists about the number of hours of sunshine per day. In health resorts and clinics, they help calculate treatment and recovery measures. In agriculture, knowledge of the sunshine duration on cultivated fields can facilitate harvest forecasting. In building automation, the sunshine duration sensor can be used to control awnings.

Measuring principle
Static methods
The sensor measures sunshine duration through a high-quality glass cylinder. It has no moving parts and uses three photodiodes with special diffusers for analog calculations of when the sun is shining. Its signal output switches to high or low for sunny or non-sunny conditions. The calculated direct radiation is also available.

The sensors are powered by 12VDC and feature a heater for use in rain, snow, and frost. The heater is usually switched externally.
Dynamic procedures
The sensor measures sunshine duration through a high-quality glass cylinder. It has moving parts and uses a photodiode with special diffusers to digitally calculate when the sun is shining. The signal output switches to high or low for sunny or non-sunny conditions. The calculated direct radiation is also available.
In this method, the measuring head rotates at a defined frequency. The sunbeam passes through a defined slit. The method also allows for spectral analysis.

The sensors are powered by 12VDC and feature a heater for use in rain, snow, and frost. The heater is normally switched externally.
Calculatory procedures
The calculation of sunshine duration is based on the addition of the time during which the 120 W/m2 limit was exceeded. A second-class pyranometer is used to measure global radiation.