When thick clouds roll in and the sun disappears, it’s easy to think solar panels just stop working, just sitting there idle until the sun shows up again.
But here’s the thing. Even on overcast days, light particles still break through the clouds – meaning your solar panels do work on cloudy days and continue to produce energy.
The real question then becomes, how much energy can you actually expect this time around, when sunlight is dimmer and less intense?
In this article, I share with you my thoughts on how solar panels perform on cloudy days, how much energy they can produce, and tips on how you can get the most out of your solar system.
Do Solar Panels Work on a Cloudy Day?
Yes, solar panels can work on cloudy days. This might come as a surprise, especially if you’ve always thought that grey skies and rain mean no sunlight at all.
The fact of the matter is, cloudy weather only blocks direct sunlight – those intense beams of bright light that make us squint when we attempt to look at the sun directly.
There remains what’s called diffuse light, which is sunlight scattered and reflected in the atmosphere. It’s much spread out and less intense, which is the case during overcast days.
With that said, when there’s a lack of direct sunlight, your solar panels utilize the weaker diffuse light to continue working. And as long as these light particles are present, you can expect your panels to keep producing electricity.
How much your solar panels will produce during these cloudy days, however, is the real concern.
By simple logic, since you’re working with low intensity sunlight during cloudy days, you can expect energy production to be much lower than what you typically get on sunny days.
How Much Do Solar Panels Produce on Cloudy Days?
How much energy output your solar panels can produce on a cloudy day depends on how much light particles they can capture and convert. Generally, the thicker the clouds are, the less sunlight there’ll be – and the lower the output tends to be.
Having tracked solar panel performance for years, I’ve seen some generate 10% less energy, while others losing as much as 25% of their rated capacity on overcast days.
This means a 5 kW system that typically produces 30 kWh might only provide anywhere between 22.5 kWh and 27kWh.
Surely, that’s a considerable drop in production. But on the bright side, I’ve never seen energy output completely plummet to zero, even under the gloomiest weather.
And this is partly thanks to a fascinating phenomenon called the cloud edge effect.
Remember those brief moments when the sun shines very intensely just before it ducks behind a cloud? This temporary burst of concentrated light can trigger your panels to deliver a higher-than-usual amount of energy, even exceeding what they typically produce under clear skies.
So, with cloud edge effect plus diffuse light combined, your solar panels will keep working to power your home, no matter the weather.
In Utah, where I and the Avail Solar team are based, cloudy days aren’t much of a concern for our folks here, especially considering the state ranks in the top 20 for solar panel installations in 2024.
Do Solar Panels Work at Night?
No, solar panels do not work at night. Once the sun sets, there’s simply no sunlight for the panels to capture, and thus no power is produced.
The good news is that while your solar panels go into rest mode, solar batteries don’t. These batteries can store the energy your panels generate during the day, which you can use later.
It was no surprise to me, then, that a few years ago, so many of my customers started asking about battery storage. People really started to want more control over their energy use – not just when the sun’s out, but especially during outages.
Now, I’ve always kept an eye on the latest tech out there, and something truly interesting (and, admittedly, a bit far-fetched) caught my attention: Technologists are actually finding ways to make solar panels work at night.
A process called nighttime radiative cooling has shown some promise in producing energy from the night sky, although the results are still limited. Researchers continue to explore its potential for more practical applications.
For now, though, I agree with the general consensus among homeowners and the solar industry. If you want to keep using solar power after dark, solar batteries are your best option.
Ways to Maximize Energy Production on Cloudy Days
There are definitely a few strategies to help one get the most out of their solar system. So, whenever a homeowner asks me, “Phill, what can I do to compensate for energy losses on cloudy days?”, here’s what I usually tell them.
Use Solar Batteries
We’ve already touched on the importance of solar batteries for nighttime use and power outages. But another key benefit that I can’t stress enough is the opportunity to take advantage of off-peak electricity rates.
On cloudy days, you can store the limited energy your panels produce and then top up your batteries by charging during off-peak periods when electricity rates are lower.
You can then draw from this stored energy during on-peak hours when grid electricity is most expensive, usually morning or late afternoon. This way, you make the most of your solar panel production and even save money as a result.
Regular Maintenance
Over time, dirt, bird droppings, and other debris can accumulate on your panels. This is oftentimes the case for homeowners living in areas prone to wildlife activity or heavy pollen.
When this happens, sunlight has a harder time reaching the surface of the panels, and this reduces their efficiency.
If your system is accessible (and if it’s safe to do so), you don’t have to wait for a professional installer to clean your solar panels. In fact, it typically just requires running tap water from a hose over them to remove the buildup.
Upsize Your Solar System Capacity
Essentially, this means adding more panels to boost your overall energy production.
Think of it like this: If you’re in a place with plenty of fish, using a larger net gives you a better chance of catching more in one go. Likewise, by increasing your system’s capacity, you can generate more energy and better meet your energy demands.
But how much larger should your system be? This is where a certified solar installer can help you.
These professionals will assess your location, local weather patterns, and energy needs to design a solar system that maximizes energy production year-round, just as we do at Avail Solar.
Work Only With the Best Solar Installer in Your Area
Choosing the right solar system for your home involves more than just picking panels. It’s also about working with a skilled solar installer who understands your local conditions and energy needs.
We, at Quote For Solar, make your search for these top-rated installers much easier. Instead of spending time researching and comparing different contractors, you’ll only have to submit a single quote request. Our team will then provide you with three competitive estimates from reputable solar companies in your area.
Each solar installer we recommend is pre-screened according to our strict quality standards to ensure they have a proven record of reliability, expertise, and customer satisfaction.
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