PerformanceUp to date · Jan 15, 2026
Temperature Coefficient
The rate at which a solar panel's power output changes with temperature, expressed as %/°C. A typical coefficient is -0.3% to -0.4% per °C — meaning output decreases as panels get hotter.
Why It Matters
In hot climates (Arizona, Texas, Florida), panels routinely reach 60-70°C on summer afternoons. A panel with -0.35%/°C loses about 14% of rated output at 65°C vs. the 25°C test condition.
Real-World Example
A 400W panel with -0.35%/°C coefficient produces about 344W when the cell temperature is 65°C (a typical hot summer afternoon).