Solar panels don’t stop working just because the sun’s behind clouds. The short answer is yes, solar panels can charge on a cloudy day—just not as efficiently.
Let’s unpack what actually happens when the sky goes grey.
How Solar Panels Work on Cloudy Days
Solar panels rely on light, not heat. Even on overcast days, light still filters through the clouds. This means solar panels will still generate electricity—just at a lower rate.
Typical performance on a cloudy day:
- Solar panels can produce 10–25% of their rated output
- Thinner clouds = higher output
- Heavier cloud cover = reduced performance
While the drop in production is noticeable, it’s not zero.
Do Solar Panels Work in the UK’s Cloudy Climate?
Yes. The UK isn’t known for its sunshine, but solar panels still make sense. Countries like Germany (with worse weather than most of the UK) have successfully scaled solar energy.
Even in cloudy areas, solar panels can be a solid investment because:
- You still get free electricity when the panels generate
- Solar battery storage can save excess power for use later
- You get paid for exporting energy back to the grid (Smart Export Guarantee)
What Affects Solar Panel Performance in Cloudy Weather?
Several factors determine how much energy your solar panels will generate during overcast days:
- Cloud thickness – Light clouds? You’ll barely notice a drop. Heavy clouds? Expect low output.
- Panel quality – Some high-efficiency panels (like monocrystalline) perform better in low light.
- System design – The tilt, orientation, and location of your panels matter.
- Time of year – Even cloudy summer days often generate more than sunny winter days.
Can Batteries Help?
Yes. If you’re worried about inconsistent sunlight, pairing your solar panels with a battery storage system is the best solution.
Here’s why:
- On sunny days, you can store extra energy for cloudy or night-time use
- Batteries reduce reliance on the grid
- Maximise your solar return, even on bad weather days
Should You Avoid Solar in Cloudy Regions?
No. Cloudy weather doesn’t make solar pointless—it just slightly reduces your peak output.
Most solar systems are designed with real-world weather in mind. When installed properly, you can still expect solid long-term savings, especially when paired with battery storage.
Bottom line: clouds affect output, not viability.
So, will solar panels charge on a cloudy day? Absolutely. While the output will be lower than on a clear day, your system doesn’t shut down. With the right setup—high-efficiency panels and a battery you can still generate, store, and use solar energy even when the sun is hiding.
Ready to go solar?
FAQs: Will Solar Panels Charge on a Cloudy Day?
No. Solar panels require sunlight to generate power. At night, they stop producing electricity completely.
Usually between 10% and 25% of their maximum rated capacity, depending on cloud thickness and light conditions.
Yes. Monocrystalline panels generally perform better in low-light conditions compared to polycrystalline.
Yes. Even with reduced performance, you still cut your electricity bills and benefit from Smart Export Guarantee payments.
It helps. A battery allows you to store excess power from sunnier periods and use it when generation is low.
Fog reduces output more than typical clouds, but panels still generate some electricity.
Yes. Solar works year-round in the UK, with systems sized to handle real conditions—not just perfect days.
Modern inverters can track lower input voltages and optimise performance even during reduced sunlight.
No. Cloudy weather doesn’t harm solar panels. Hail or storms can, but good panels are tested for durability.
Not necessarily. Cleaning frequency depends more on pollution or debris than weather.
