If you’re going to get a solar panel system, you want it to be worth the investment – and in our often cloudy country, it’s easy to question whether you’ll save much on your energy bills.

Fortunately, solar panels work well with any kind of natural light, and a good installer will ensure your system makes the most of the direct (and indirect) sunlight it receives.

In this guide, we’ll explain how this works, how clouds could affect your system, and what you can do to maximise your solar panels’ output in all conditions.

If you’re wondering how much you could save with a solar & battery system, enter a few details below and we’ll provide an estimate.

Do solar panels only work in direct sunlight?

Solar panels work in direct and indirect sunlight, as they just need daylight to function.

A rooftop system is ready to go at any time – all it needs to produce electricity is a supply of photons to dislodge the electrons in the panels’ silicon atoms.

Photons are present in all types of natural light, so whether the sun is shining directly onto your panels, reflecting off your pond, or coming through clouds, it’ll make your system generate electricity.

So at any time during the day, your panels should function. They just won’t work at night.

To fully thrive though, direct sunlight is better for panels, as it’s a more plentiful source of photons. That’s why solar installations in places that often enjoy clear, sunny skies – such as California, Egypt, and Spain – produce so much electricity.

In contrast, when sunlight reflects off surfaces like clouds and buildings, it scatters. This reduces the light’s intensity, also known as its ‘solar irradiance’, and you end up with indirect (or ambient) light.

However, solar panels still work extremely well in the UK, despite our frequently cloudy weather. We’ll explore this more below.

And for more information on the science behind solar, check out our guide to how solar panels work.

Do solar panels work on cloudy days?

Solar panels do indeed work on cloudy days, though their output varies depending on the amount of cloud cover.

Light clouds, such as delicate, wispy cirrus varieties, will naturally have a much smaller impact on your solar panel output than thicker types, like cumulus clouds.

None of these clouds will block the light entirely, though. Unlike buildings or humans, which cast sharp, well-defined shadows, clouds scatter all the light that hits them – and some of these rays will hit your panels.

And even when it is heavily overcast and your system’s production levels are low, you can take comfort in the knowledge that any rain will clean your solar panels and improve their output moving forward.

What’s the impact on solar output?

Clouds certainly reduce solar output, but it’s not totally clear by how much, and the phenomenon hasn’t been researched much in western Europe.

However, recent studies in Uzbekistan and Nigeria have shed some light on the subject, and provide a useful – if not definitive – indication of how clouds affect solar production levels.

In 2025, a scientist at Tashkent State Technical University found that light cloud cover reduces solar output by 30% to 70%, depending on exactly how light it is.

On the other hand, the research indicated that heavy cloud cover can result in output losses of 90% to 95% – though still never 100%.

And in 2023, research by physicists at Nigeria’s University of Port Harcourt showed a 23.8% drop in output due to light cloud cover, and a 66.8% reduction when there was heavy cloud cover.

This may sound like a large drop in output, but the average solar panel system in the UK still produces enough electricity to massively reduce your energy bills (more on this below).

And when the clouds move on, your system should ramp back up to full productivity pretty much straight away.

What is the ‘edge of cloud’ effect?

The edge-of-cloud effect – also known as ‘cloud edge glint’ or ‘cloud enhancement’ – can temporarily increase solar output.

When sunlight shines through the very edge of a cloud, its water molecules scatter and bend the light, making it more concentrated as it passes through.

The edge-of-cloud effect typically causes a temporary 47% spike in solar output when sunlight passes through one cloud, according to University of California San Diego researchers.

When the light goes through the edges of two clouds, you can expect a 63% increase in solar output, on average.

Evidently, some clouds come with a silver lining, but a clear sky is still your best bet for maximum solar output.

In fact, a solar & battery system can save you 86% on your electricity bills across the year, on average.

This figure is based on a sample of over 150 systems installed by Sunsave across England and Wales in 2024. The average system is 6.1kWp, with 54% of solar electricity used at home and 46% exported to the grid.

Ensuring strong solar output in cloudy weather

To make sure your system produces as much electricity as possible, even in cloudy weather, you should choose one of the best solar panel installers around.

A good installer will design the most effective system for your home, which involves making the most of your roof space, optimising your panels’ angle and direction, and not cutting any corners – with either your kit or the installation itself.

It’s only with a properly installed system that you can maximise your energy bill savings, helping you reach – or exceed – the 86% savings figure we mentioned earlier.

If you’re wondering how much you could save with a solar & battery system, enter a few details below and we’ll provide an estimate.

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