In general, monocrystalline silicon solar panels tend to have higher power generation efficiency compared to polycrystalline silicon solar panels, both in sunny and cloudy/rainy conditions. This is because monocrystalline panels are made from a single crystal structure, which allows for better electron mobility and more efficient conversion of sunlight into electricity.

During rainy days or cloudy conditions, the amount of sunlight reaching the solar panels is reduced, which affects their overall efficiency. However, monocrystalline panels typically perform slightly better in low-light conditions due to their higher efficiency and better response to diffuse light. This means that even though both types of panels will experience reduced efficiency on rainy days, monocrystalline panels may still outperform polycrystalline panels.

It’s important to note that the actual performance difference can vary depending on various factors, including the specific brand and quality of the solar panels, the design of the system, and the local weather conditions.