How Does the Weather Affect Solar Panel Efficiency?


It’s a beautiful sunny day here in Shenzhen, China. There’s not a cloud in the sky, and a cool spring breeze is whistling through the blossoming trees. But as any good Chinese knows, the weather can change in a matter of minutes, and it’s best to be prepared for any occasion.

In the same vein, if you’re considering getting solar panels for your home, it’s important to understand how the weather will affect solar panel efficiency. If for instance, your home is located in a region prone to hail and lightning, it may be in your best interest to look at higher quality panels or additional grounding equipment.

The good news—and there’s always good news with solar energy—is that photovoltaic (PV) solar panels have evolved to become incredibly durable, even in Earth’s most extreme environments. You’ll find them in Antarctica and Iceland. You’ll find them in the scorching heat of the desert. Once you’re satisfied that they’re a good investment, you may soon find your very own money-saving solar panels on your roof!

Solar Panels and Cloudy Days

There are some pretty standard myths that have unfortunately been attached to any talk of going solar, but the question “Do solar panels work on cloudy days?” is by far the most popular. Before we can understand the effect clouds will have on system efficiency, we first must understand what’s important to the smooth operation of your solar panels—namely sunlight.

In the simplest terms, solar panels need access to the Sun’s energy which makes the 93 million mile journey to Earth in the form of photons. When photons strike a panel, they are converted into direct current (DC) electricity. After being converted to alternating current (AC) electricity via the system’s inverter, you have useable solar energy for your home.

When it comes to weather, you’re generally always going to have significant cloud cover regardless of there’s rain, lightning, hail, or snow. These clouds effectively reduce the amount of sunlight that can reach your solar panels. Depending on how dark and heavy the rain and clouds can be, your solar panels will likely see a sizeable drop in efficiency.

Take, for instance, the example of the blanket and the flashlight. If you’re in a dark room divided by a blanket, and one person shines a flashlight on the blanket, a person on the other side would be able to see the light. Supposing you divide the room with more blankets or a darker, thicker blanket, the person on the other side would see less light. The same principle is true with solar panels. The Sun would be the flashlight, and the solar panels would be the person on the other side of the blankets (clouds).

The reason the “solar panels don’t work on cloudy days” idea is a myth, is because even though you can’t see the Sun, light is still getting through the clouds, even if only a little. Keep in mind we wouldn’t even be able to see anything if light wasn’t getting through!

Luckily solar panels absorb both direct light and diffuse light; that is—light that is not directly shined from the Sun onto the panels. This light is reflected off of clouds, buildings, and other shiny, light-colored surfaces. With any sunlight, your solar panels will produce electricity. Conversely, this is why solar panels do not produce at night time.

If you have any additional questions about going solar or potential weather effects, do not hesitate to contact us. And remember, even on the cloudiest days, the Sun is still shining brightly in the sky!