Category:

Solar panels

Blog

Do Solar Panels Work in Winter UK? Efficiency & Output

Did you know the UK gets around 8 hours of daylight in winter compared to 16 hours in summer? That’s a significant drop, raising a common question: Do solar panels work in winter in the UK? Many homeowners worry that cloudy skies and colder temperatures might render their solar panels ineffective. But is that really the case? The good news is that solar panels still generate electricity in the winter, even on cloudy days. While their output is lower compared to the summer, they can still contribute significantly to your energy needs. The key is understanding how they work in winter conditions and what you can do to maximise their efficiency.

Key Takeaways

Solar panels work in winter but with reduced efficiency due to shorter daylight hours
Solar panels work in cloudy weather by capturing diffused sunlight
Solar production is lower in the winter than in the summer but can still contribute to energy savings
Maximise efficiency by keeping panels clean, using high quality inverters and installing battery storage
Solar panels actually work better in cold weather and only struggle under heavy snow

In this post, we’ll cover:

How solar panels generate electricity in winter and cloudy weather
The impact of cold temperatures and daylight hours on efficiency
Solar panel output in winter vs. summer in the UK
Ways to maximise performance during the winter months
Why year-round solar energy generation is still a great investment

Do Solar Panels Work Without Sun or in Cloudy Weather?

Many people assume that solar panels need direct sunlight to function. But in reality, solar panels can still generate electricity on cloudy days. This is because they rely on daylight rather than direct sunlight.

How Do Solar Panels Work in Cloudy Weather?

Solar panels use photovoltaic (PV) cells to convert daylight into electricity. Even when the sky is overcast, some sunlight still reaches the earth and is absorbed by the panels. This is called diffused sunlight, which allows solar panels to continue producing energy, albeit at a lower efficiency.

Factors that Influence Solar Panel Efficiency in Cloudy Weather

Cloud Density: Light cloud may allow more sunlight through, while thick, dark clouds reduce output
Angle of the Sun: A low sun angle in winter results in lower energy production
Panel Quality: High-efficiency solar panels perform better in low-light conditions

👉 On heavily overcast days, solar panels may produce 10-25% of their maximum output, but they will still generate electricity.

What About Rain and Snow?

Rain can actually help by washing away dust and debris, keeping your panels clean.
Snow rarely causes problems in the UK, but if panels are completely covered, production will pause until they are cleared.

💡 Bottom line: Even in cloudy weather, solar panels still generate electricity – just at a lower rate.

How Efficient Are Solar Panels in Winter? Impact of Winter Conditions on Solar Panels

Winter in the UK brings shorter days, lower temperatures and more cloudy skies – but does that mean solar panels become ineffective during the winter months? Not at all! In fact, solar panels work more efficiently in cooler temperatures compared to extreme heat. However, their overall output is lower due to reduced daylight hours.

Effect of Shorter Daylight Hours on Solar Panel Output

One of the main reasons winter energy production drops is the limited sunlight exposure.

In summer, the UK gets up to 16 hours of daylight
In winter, this can drop to just 8 hours or less

Since solar panels rely on daylight rather than heat, fewer daylight hours naturally lead to lower energy production. With fewer daylight hours in winter, solar panels will generate less electricity compared to during the summer.

How Much Do Solar Panels Generate in Winter in the UK?

On average, solar panels in the UK produce around 20-30% of their peak summer output during the winter months. The exact figure depends on factors like:

Panel orientation: South-facing panels capture the most sunlight.
Weather conditions: Frequent overcast days mean lower output.
Shading: Trees, buildings, or snow can reduce efficiency.

Example:

A 4kW solar system may generate 15-20 kWh per day in summer but only 3-6 kWh per day in winter.

At What Temperature Do Solar Panels Stop Working?

Unlike some electronic devices, solar panels perform better in colder temperatures. The ideal working temperature for solar panels is around 5-25°C. However, extreme weather conditions can affect them:

Cold weather (0°C and below): Panels still function but may be affected by heavy snow.

Heavy snow accumulation: If panels are fully covered, they temporarily stop producing electricity.

Icy conditions: Rare in the UK but can impact efficiency if ice builds up.

💡 Key takeaway: While solar panel output is lower in winter, they still provide valuable energy savings, especially when combined with a battery storage system.

Solar Panel Output Winter vs Summer in the UK

Solar panel performance varies significantly between winter and summer due to changes in daylight hours, weather conditions and sun intensity. Here’s a closer look at the differences.

Winter vs. Summer Solar Energy Production

Factor	Summer	Winter
Daylight Hours	~16 hours	~8 hours
Sun Intensity	Stronger, direct sunlight	Weaker, diffused sunlight
Temperature Effect	Higher temperatures can slightly reduce efficiency	Colder temperatures improve efficiency
Average Daily Output	15-20 kWh/day	3-6 kWh/day

Why Is Solar Output Lower in Winter?

Less daylight: Fewer sunlight hours mean reduced electricity generation.

Lower sun angle: The sun stays lower in the sky, reducing direct exposure.

More cloud cover: Overcast days lead to weaker solar output.

Potential shading: Trees and buildings cast longer shadows in winter.

Case Study: UK Solar Panel Performance in Winter

A study of UK solar panel installations found that:

3.5 kW system in London produced 3-5 kWh per day in December, compared to 18-22 kWh per day in July.

Even in Scotland, where daylight hours are shorter, solar panels still generated around 20% of their peak summer output in mid-winter.

💡 Key Takeaway: While winter output is lower, solar panels still produce enough energy to reduce electricity bills, especially when combined with battery storage.

Keep on reading: Solar Panel Output

The Solar Bell

The graph below shows the monthly breakdown of annual solar energy generation. The curved shape it creates, referred to as ‘The Solar Bell’, demonstrates that solar generation is at it’s peak from April through to September due to longer daylight hours and sunnier weather. While solar generation may be lower in the winter months, the best time to install solar panels tends to be in February or March, so you’re ready to take advantage of clean solar energy during the months of peak performance.

Save Even More: How to Optimise Your Solar PV Yield in Winter

These simple steps can help you get the most out of your solar PV system, even during the shorter, cloudier winter days in the UK.

Panel Angle

The performance of a solar PV system in the UK is greatly influenced by the tilt angle of the panels. A south-facing roof with a tilt angle of around 30-40° typically provides the best year-round performance. This angle strikes a good balance, capturing low winter sun while still performing well in summer.

Battery Storage

By storing excess electricity generated during the day, you can use more of your own energy in the evening and reduce reliance on the National Grid. With a good battery setup, self-consumption rates can rise to 50-80%, helping to cut energy bills and improve energy independence.

System Size

The number of solar panels you install directly impacts how much electricity you can generate. It's important to size your system based on your household’s electricity usage to ensure you get the best return without overspending on capacity you don't need.

Benefits of Year-Round Solar Energy Generation

Investing in solar panels isn’t just about summer sunshine - they provide valuable benefits all year round, even in winter.

Here’s why solar energy remains a great choice regardless of the season.

1. Energy Savings and Reduced Bills

Even in winter, solar panels help cut electricity costs by generating clean energy from daylight.
The more energy you generate, the less you rely on expensive grid electricity.
Pairing panels with battery storage ensures you can use solar energy even after sunset.

2. Return on Investment (ROI) and Long-Term Value

Solar panels typically pay for themselves in 6-10 years, depending on energy prices and usage.
Government incentives like the Smart Export Guarantee (SEG) allow homeowners to sell excess energy back to the grid, further improving ROI.
Since panels last 25+ years, they continue to save money long after they’ve paid for themselves.

3. Environmental Benefits: A Sustainable Energy Choice

Using solar power reduces reliance on fossil fuels and lowers your carbon footprint.
Even in winter, solar panels cut CO₂ emissions by reducing the need for coal or gas-generated electricity.
Solar energy supports the UK’s net-zero targets for a greener future.

4. Energy Independence & Protection from Rising Prices

Solar panels reduce reliance on energy suppliers, making households less vulnerable to electricity price increases.
With battery storage, homeowners can store excess solar power for later use, reducing dependence on the grid.

Introducing Soly: Solar Solutions for All Seasons

At Soly, we understand that solar energy isn’t just for summer – it’s a year-round investment in savings, sustainability and energy independence. That’s why our solar solutions are designed to perform efficiently even in UK winters.

Why Choose Soly?

High-Efficiency Solar Panels: Our panels are optimised for low-light conditions, ensuring steady performance even on cloudy days.
Smart Battery Storage: Store excess energy and use it when you need it most, even after sunset.
Tailored Installations: We assess your home’s unique conditions to maximise efficiency and output.
Expert Support & Maintenance: From installation to ongoing monitoring, we’re with you every step of the way.
Great Return on Investment: With our solar solutions, you can reduce energy bills and take advantage of the Smart Export Guarantee (SEG).

Power Your Home with Soly’s Smart Solar Solutions

No matter the season, Soly helps homeowners harness solar energy efficiently. Whether you want to lower your electricity bills, reduce your carbon footprint, or gain more energy independence, we have the perfect solution for you.

💡 Want to learn more?

Try our online configurator and book a free online consultation to find out how much you could save with solar!

Background

Knowledge Base

While you are still here: have a look at our knowledge base. It's full of information concerning the benefits and possibilities of solar energy. And we do our bit. Here are some of the most interesting topics we already covered.

Visit knowledge base

Do you need to clean solar panels?

Over the years, the panels are exposed to numerous conditions such as rain, wind, snow, sand, and moss. Do you need to clean your solar panels every once in a while?

How much CO₂ emissions can be saved with solar panels?

In addition to the financial benefits, lower carbon emissions is also a good reason to have solar panels installed. How much CO2 will you save?

Difference between serial and parallel connection of solar modules

“My roof is partly in the shade, but I would like solar panels. Is that possible?” This is a question we often hear during telephone consultations. We'll tell you more about it.

How many solar panels do I need?

This is a common question people ask themselves when they are considering whether to purchase or rent solar panels. So, how about it?

Visit knowledge base