Solar panels generate the most electricity when they receive intense, unobstructed and direct sunlight. Cloudy, rainy, and darker days will therefore generate less electricity. However our exclusive SunPower Solar Panels uses “cells with a unique one-of-a-kind design that capture a broader range of the sun’s light — including red and blue wavelengths. They make more energy than conventional panels on a cloudy day, making them a good choice for cloudy climates or if trees partially shade your roof during certain times of day.” Please check this link for the full article source.