How Do Solar Panels Work on Cloudy Days?

When exploring solar panel options for your home, a common question many homeowners ask is how well their system will perform when the sky is overcast.

Here in California, we’re familiar with varied weather patterns—so what does that mean for your solar energy production? The good news is, even on cloudy days, your solar panels continue generating electricity. With California enjoying abundant sunshine throughout the year, there’s plenty of sunlight to power your home. Of course, we also experience occasional cloudy spells—so let’s take a closer look at how cloud cover may impact your system.

How Efficient Are Solar Panels on Cloudy Days?

On heavily overcast days, your solar panels can still produce around 25% of their typical energy output. While that might sound low, remember—sunny days will return, and your system will soon be back at full production. Thanks to net metering policies, you won’t experience any interruption in power. Since your system remains connected to the grid, your utility company supplies extra electricity whenever your panels aren’t producing at full capacity—whether that’s at night or during cloudy weather.

For greater energy independence, you might consider a solar battery storage system. Watts Up Energy collaborates with trusted battery partners and would be glad to discuss options tailored to your needs.

Can Clouds Actually Improve Solar Production?

It may come as a surprise, but certain cloudy conditions can actually enhance your energy generation. When clouds are scattered, sunlight can reflect off them and back toward your panels—effectively giving your system an extra energy boost. In some cases, clouds may even magnify sunlight, leading to higher-than-expected power output.

Modern solar systems are designed to maximize energy production even under challenging conditions. While shaded panels might produce less, those in full sun will continue operating at peak performance.

Rain can be beneficial, too. A passing shower helps wash away dust, pollen, and debris from your panels, improving their efficiency and output.

Can Too Much Sun Affect Solar Panels?

While it’s true that solar panels thrive in sunlight, extremely high temperatures can actually reduce their efficiency. In fact, intense heat may cause panel output to drop by 10–25%. Solar panels, like other electronic devices, can overheat.

Here in California, we’re fortunate to have a Mediterranean climate that helps avoid prolonged extreme heat. Occasional rain and cloud cover help cool your panels, allowing them to operate at ideal temperatures and maintain better overall performance.

Go Solar Today