Can Solar PV Panels Work During Cloudy or Rainy Days in the UK?

It’s completely natural for homeowners in Somerset to wonder how well solar PV panels perform when the weather turns cloudy, dull or rainy — especially with our famously unpredictable skies. The good news is that modern solar technology is far more capable than many people realise. Even on overcast days, your system can continue generating clean, reliable electricity, helping you lower your bills and reduce your carbon footprint.

In this guide, we explain exactly how solar panels behave in cloudy or rainy conditions, what affects output, and how you can prepare your home to get the best results year-round. If you’re researching solar for the first time, you can read more about the basics of what a solar PV system is. If you’re already planning your installation, our dedicated page on solar PV installations is a great place to start.

Do Solar PV Panels Work on Cloudy Days? Yes — and Better Than Most People Expect

Solar PV panels don’t rely on direct sunlight alone. They generate electricity from visible light, which still penetrates cloud cover. This means your panels will continue producing power even when Somerset faces grey skies or light rain.

Here’s what we typically see with well-installed systems:

On bright, sunny days: 100 percent output
On lightly cloudy days: 50 to 80 percent output
On heavily overcast days: 10 to 25 percent output
During rain or winter gloom: lower, but still generating

The exact numbers depend on the panel type, roof angle, shading and installation quality. If you’re curious about different panel options, our guide on which PV solar panels are the best provides a simple breakdown without the jargon.

How Rainy Weather Affects Solar PV Performance

Rain does reduce output slightly because raindrops scatter sunlight. However, rain actually helps your system in other ways:

It naturally cleans the panels
It washes away dust and pollen
It improves long-term panel performance
It helps prevent hotspots caused by dirt build-up

Many customers are surprised to see their solar system performing better after a rainy day, especially in spring and early autumn.

If you’d like to understand the science behind how panels create electricity in the first place, our article on how solar PV panels generate electricity is a helpful and easy-to-follow guide.

Why Solar Works So Well in the UK Climate

Although we’re not blessed with Mediterranean sunshine, the UK is ideal for solar because panels don’t actually need heat — they need light. In fact, solar panels operate more efficiently in cooler temperatures.

Somerset, with its mild climate and long daylight hours throughout spring and summer, often sees better performance than many homeowners expect. Our customers regularly comment that they assumed grey weather would stop production entirely — but modern PV technology continues to deliver power consistently.

If you’re comparing different solar technologies, our article on solar PV vs solar thermal may help you understand which option best suits your goals.

How Much Power Can Solar Produce on a Cloudy or Rainy Day?

Homeowners often ask for “real numbers”, so here’s a simplified example:

A typical 4kW system in Somerset:

Sunny summer day: around 18–22 kWh
Lightly cloudy day: around 9–14 kWh
Overcast day: around 3–6 kWh
Winter rainy day: around 1–3 kWh

These figures vary, but they provide a realistic picture of what you can expect throughout the year.

For more detailed insights, you can read our guide on how much electricity solar panels produce per day in the UK.

What Helps Solar Panels Perform Better During Poor Weather?

There are several factors that influence how well your solar PV system manages cloudy or rainy conditions:

1. Panel Type and Efficiency

Higher-efficiency mono-crystalline panels perform far better than older polycrystalline models. If you’re exploring which panel size or type suits your property, our guide on what size solar PV panels are breaks this down clearly.

2. Roof Angle and Direction

South-facing roofs perform best, but east/west roofs also perform strongly.

3. Shading

Tall trees or chimneys can affect output, especially in winter.

4. Installation Quality

A well-designed and properly installed system significantly improves year-round performance. Our team follows strict quality standards when installing panels, which you can learn more about in our article on roof-mounted solar installations.

5. Battery Storage (Optional)

Battery storage allows you to save sunny-day surplus for cloudy evenings — ideal for Somerset homes with higher evening usage.

Will Solar Panels Still Save You Money on Cloudy Days?

Absolutely. Even with reduced generation, your system still offsets a portion of your grid usage. With modern energy prices, even partial generation during cloudy periods can lead to meaningful savings over the year.

Here’s why solar remains financially strong in the UK climate:

Lower electricity bills
Reduced evening grid usage with battery storage
Payments through Smart Export Guarantee
Increased home value
Long panel lifespan (25–30 years)

We regularly share updates about solar performance and savings in the UK through our news section.

How to Prepare Your Home for Solar PV Installation (Somerset-Specific Tips)

Many homeowners want to maximise performance before installation. Here’s the preparation guidance we share with Somerset customers:

1. Assess Your Roof Condition

A stable roof with no structural issues ensures a smoother installation. If your roof needs minor repairs, it’s worth completing them beforehand.

2. Check for Local Considerations

Somerset properties can vary — cottages, barns, modern builds and coastal homes each have different requirements. We always tailor recommendations to your specific property type.

3. Clear Nearby Trees or Overhanging Branches

Shading is one of the main factors that reduces output during cloudy conditions.

4. Review Your Energy Usage

Understanding your daily consumption helps us design the right system size for you.

5. Choose Certified Installers

Always work with a qualified local team who can install your system safely and help you make sense of all the technical details. We pride ourselves on this level of support and transparency throughout the process.

Benefits of Solar PV During the UK’s Cloudiest Months

Even during Somerset’s cloudiest days, homeowners continue to see benefits from their solar systems.

Less reliance on the grid
Lower energy bills
Protection against rising energy prices
Cleaner, renewable electricity
Stronger energy independence
Predictable long-term financial return

Solar panels are designed to work in a wide range of real-world conditions, not just perfect blue skies — and this adaptability is one of their biggest strengths.

Frequently Asked Questions About Cloudy Weather and Solar PV

Do solar panels stop working when it rains?

No, they continue generating electricity — just at a reduced level.

Do solar panels work without direct sunlight?

Yes. They need light, not heat.

Is solar still worth it in a cloudy county like Somerset?

Absolutely. Most Somerset homeowners still see strong long-term savings.

Can I add a battery later if I don’t want one now?

Yes, many systems allow batteries to be installed later.

Final Thoughts

Solar PV systems absolutely can work during cloudy and rainy days in the UK — and they often perform better than homeowners expect. Somerset’s climate is far more solar-friendly than people realise, and a well-designed installation will deliver reliable year-round benefits.

If you’re ready to move forward or you’d like friendly, expert advice about the next steps, you can reach our team any time through our contact page. You can also explore our dedicated guide to solar PV installations to see how we support homeowners across Somerset.