Calculate solar panel power output at any operating temperature using the temperature coefficient (γ).
Typical: -0.25 to -0.50 %/°C
P_op = P_STC × [1 + (γ/100) × (T_op − T_STC)]
The temperature coefficient (γ) shows how much power decreases per °C above 25°C. Modern monocrystalline panels typically range from -0.25% to -0.35%/°C, while polycrystalline panels are often around -0.40% to -0.50%/°C.
Apply P_op = P_STC × [1 + (γ/100) × (T_op − 25)]. Enter the panel's rated wattage, its temperature coefficient from the datasheet, and the expected cell operating temperature to get the real-world output.
A good coefficient is closer to zero. Premium panels reach -0.26%/°C or better. In hot climates, every 0.1% improvement can mean significant energy gains over a system's lifetime.