Do Solar Panels Work on Cloudy Days? What You Need to Know in the UK

Do Solar Panels Work on Cloudy Days? What You Need to Know in the UK

The short answer? Yes, they do.
The longer answer? Let’s break it down, with real-world data, no nonsense, and expert advice from The Green Way Solar.

Can Solar Panels Generate in Cloudy Weather?

Yes. Solar panels generate electricity using light, not heat, so even on overcast days, your system will still produce power.

The amount will vary depending on:

Typical output on a cloudy day = 10–40% of what you’d get on a bright, sunny day.

Example: A 6kWp system in Milton Keynes might produce:

  • 25–35kWh on a sunny summer day

  • 6–10kWh on a cloudy spring/autumn day

  • 2–4kWh on a gloomy winter day

Solar Panels on Cloudy Day

Why High-Efficiency Panels Matter

At The Green Way Solar, we install ultra-efficient panels that outperform on low-light days.

We use:

  • Aiko 

  • Eurener

  • Trina

  • Longi

  • Jinko

  • Perlight

  • Viridian Clearline Fusion (for in-roof systems)

These panels are tested to perform well in Northern Europe’s cloudy, damp, and often hilariously grey conditions.

Batteries + Cloud = Game Changer

Adding a battery completely changes the equation. On cloudy days:

  • Your system still generates something

  • You can top up overnight using cheap off-peak tariffs like Octopus Go (from 8p/kWh)

  • Your battery covers your usage the next day

“Our setup uses 4.2kWp solar, 19kWh of storage and 3 EVs. Even in December, we charge the battery every night at 8p and average under 10p per kWh across the year.”
– Danny Hirst, MD, TGWS

The Hidden Benefit of Cloud Cover

Believe it or not, a bit of cloud can sometimes increase generation slightly. It’s called the edge of cloud effect, when sunlight bends around cloud edges and intensifies briefly, spiking panel output for a few moments.

You might notice your system occasionally over performing just before or after a cloud passes.

Real Results from The Green Way Solar Systems in Winter

  • Bedford bungalow – 3.6kWp, no battery
    Winter average: 3.5–5kWh/day
    March–October: 12–18kWh/day

  • Luton family home – 6.4kWp + 13.5kWh battery
    Winter average: 5–8kWh/day solar + overnight battery top-up
    Savings continue year-round

  • Bletchley flat roof – 7.2kWp + zappi charger
    Cloudy day generation: 8–12kWh
    Car charged 60% using solar even in February

💬 FAQs

Q: Is solar worth it if the UK is cloudy most of the year?
Yes, because the UK still gets over 1,000 hours of usable sunlight per year. And with a battery, you flatten out the peaks and troughs.

Q: Will my system work in winter?
Absolutely. It’ll generate less, but it will still work, especially with high-performance panels and smart load planning.

Q: Should I get a bigger system to make up for cloudy weather?
Only if you’ve got the roof space and usage to match. We’ll design the right size to balance savings vs payback.

Q: Do I need a south-facing roof?
Nope. East/west and even some north-east/north-west roofs still perform surprisingly well with today’s panel tech.

Why Trust The Green Way Solar?

We specialise in smart solar solutions that work all year round, not just on sunny days.

  • Tesla Powerwall 3 Certified

  • SolarEdge and FoxESS advanced installers

  • Experts in EV, battery and time of use optimisation

  • Covering Beds, Bucks, Herts, Northants, and Milton Keynes

We design for real UK conditions, not fantasy weather.

✅ Final Verdict: Do Solar Panels Work on Cloudy Days?

✔ Yes, just not at full output
✔ They still generate usable power
✔ Batteries make cloudy days easy to ride out
✔ A well designed system works year round, even in the UK

Solar’s not about chasing sun, it’s about using what you get wisely. That’s what we do.