Solar panels in winter, cloud and snow Do solar panels work in winter?
Yes, but they make a lot less. Solar panels run on daylight, not heat, so they keep generating electricity on cold and cloudy days. UK home systems make roughly a third as much from October to December as from April to June. If you're weighing up solar, here's what to expect in winter, cloud, snow and at night, with government figures, and how to plan around it.
Winter vs summer energy production, in numbers
How solar panels generate electricity without direct sunlight
Solar panels are made of photovoltaic (PV) cells, most commonly silicon. When light reaches the cells they produce DC electricity, and an inverter turns that into the AC electricity your home runs on. That's the whole process, and it needs light, not heat or a blue sky.
The Energy Saving Trust says panels work best in direct sunlight but still generate electricity on cloudy days, because they absorb energy from visible light and from wavelengths that pass through cloud. So a solar panel system keeps producing usable electricity through the winter months, just less of it. For the full path from roof to plug socket, see how do solar panels work?
Why solar panels produce less electricity in winter
The Energy Saving Trust gives three reasons: the days are shorter, it's more likely to be cloudy, and the sunlight isn't as intense because the sun is lower in the sky. Fewer daylight hours and a low sun mean less energy reaches the panels each day.
The government's figures show the effect clearly. Its analysis of more than 280,000 small solar installations on the Feed-in Tariff found October to December 2024 was the weakest quarter of the year, with a load factor of 4.7%, and April to June the strongest, at 13.6%. A load factor is what a system actually generated as a share of what it could have made running flat out all the time. In DESNZ's words, generation is boosted when the sun shines for longer and is weaker in winter months.
Weather conditions matter from year to year too. In the government's figures, which start in 2001, 2024 had the lowest average sun hours and 2025 the longest. Solar energy production in a dull winter can be noticeably lower than in a bright one.
Do cold temperatures reduce solar output?
No. Cold isn't the problem. Solar panels are slightly more efficient in cooler temperatures, and lose a little output as they heat up. Panels are rated at a cell temperature of 25°C, and makers publish a temperature coefficient: how much output changes for each degree above or below that. It varies with the solar technology. A 2026 Trina Vertex S+ panel loses about 0.29% of its output for every degree it heats up, and a REC Alpha Pure-RX heterojunction panel about 0.24%.
In use, the cells run much warmer than the air. Trina's datasheet puts them at about 43°C in strong sunlight with the air at 20°C and a light breeze. Cold temperatures keep the cells cooler, closer to or even below their rated 25°C, which helps efficiency, so a bright, frosty day can be surprisingly productive. The same panel is rated to work from -40°C to +70°C, well beyond any UK winter conditions.
So heat, not cold, is what dents efficiency. Lower winter output is down to shorter days, cloud and a low sun.
Do solar panels work on cloudy days?
Yes. Panels don't need direct sunlight. They generate from daylight, including the diffuse light that comes through cloud, with a lower output. How much lower depends on the cloud cover: light clouds on a bright overcast day still let plenty through, while heavy, dark cloud cuts output sharply.
We haven't found an official figure for how much a cloudy day makes compared with full sun, and the percentages quoted online vary a lot, so treat any single number with care. What the yearly figures do show is that UK weather, cloud and all, still gives a useful amount of electricity over a year.
And when it rains?
Rain usually means thick cloud, so output is low while it lasts. It helps in another way: the Energy Saving Trust says rain will clean UK panels tilted at 15 degrees or more, so most pitched roofs need little cleaning.
Shade, and why it matters more in winter
Panels still work in partial shade, but it costs output, and it matters more in winter. A low sun casts longer shadows, so chimneys, trees and neighbouring buildings shade more of a roof in winter than in summer. The Energy Saving Trust says nearby buildings, trees or chimneys can reduce a system's performance, and Which? says heavy shading (more than 80%) can cut output by up to 50%.
If part of your roof is shaded, optimisers or microinverters can limit the effect on the rest of the panels. The Energy Saving Trust notes they add nothing where there's no shade. See solar optimisers and microinverters.
Snow, frost and how panels clear
- A covering of snow blocks the light, so solar panels make little until it clears.
- Panels are smooth and tilted, and they warm slightly in daylight, so snow usually melts or slides off without help.
- Leave any snow buildup to clear on its own. Don't go on the roof: it isn't worth the risk, and scraping can damage the glass.
- Frost on its own clears quickly once the sun reaches the panels.
The weight of heavy snowfall isn't usually a worry for the panels themselves: Trina's datasheet, for example, lists a test snow load of 5,400 Pa, roughly 550 kg on each square metre. And a few days under snow costs only those days' output, which in winter is a small share of the year anyway: October to December made about 10% of the UK's solar output in 2025.
At night and in a power cut
Panels need light, so they don't generate at night: solar power stops at dusk. They don't work in a power cut either, even in daylight: the Energy Saving Trust says panels typically can't power your home during a power cut unless the system has extra equipment, because they switch off by design so they can't feed the grid while engineers work on it.
A battery changes the picture. It can store spare daytime solar for the evening and, in winter, charge overnight on a cheaper tariff to cover the expensive daytime and evening hours. See are solar batteries worth it?
What winter means for your electricity bills
In winter your panels cover less of what you use, so you'll buy more from the grid and your electricity bills won't fall as far as they do in summer. Homes with a heat pump or an electric car usually need more electricity in winter, just when panels make least.
That makes the solar you do generate worth more if you use it yourself. From October to December 2026, Ofgem's price cap puts grid electricity at an average of 26.32p a unit (VAT has been removed from electricity bills until 31 March 2027). When we checked, the Energy Saving Trust worked on export payments of around 12p a unit. At those rates, every unit you use rather than export is worth more than twice as much.
Judge solar energy over a year, not a day
Solar works year round, but it's judged over a year. Long spring and summer days bring far more electricity, and those surpluses, exported or stored, balance out the winter shortfall. In 2025, April to June produced about 42% of the UK's solar output and October to December about 10%. When you compare quotes, look at the estimated yearly generation, not what the panels make on a grey January afternoon.
How well solar panels perform in December matters less than the yearly total, and that's what payback figures use. The Energy Saving Trust's estimates, with export payments, put payback at 9 to 12 years in its examples, from London to Stirling. The Energy Saving Trust also says a typical home system could save around one tonne of carbon a year.
Getting more from winter energy generation
| Do this | Why |
|---|---|
| Run appliances in the middle of the day | Winter output peaks around noon, and is short |
| Use a time-of-use tariff | Charge a battery or car overnight when electricity is cheapest |
| Check your app after heavy snowfall or a storm | Spot anything blocking the panels or a fault early |
| If you have a choice of slopes, favour south | In the northern hemisphere, a south-facing slope catches more of the low winter sun |
| Keep an eye on new shade | A growing tree can shade more of the roof each winter |
In the north, winter days are shorter, but northern summer days are longer, and the government's data shows home solar in the North East performing among the best regions in England over a full year.
Questions people ask
Do solar panels work in winter in the UK?
Yes. They generate less, because days are short and the sun is low, but they keep working. UK home systems made roughly a third as much in October to December 2024 as in April to June.
What are the worst months for solar panels?
In the UK, October to December. In the government's 2024/25 figures it was the weakest quarter for small solar systems, with a load factor of 4.7% against 13.6% from April to June.
Do solar panels work on cloudy days?
Yes, at a lower rate. They generate from daylight, including light that comes through cloud cover.
Do solar panels need direct sunlight?
No. Direct sun gives the most output, but panels generate energy from any daylight.
Do solar panels still generate when it's raining?
Yes, but output is low under thick rain cloud. Rain also helps keep tilted panels clean.
Can solar panels produce electricity in the shade?
Yes, but shade reduces output, and Which? says heavy shading can cut it by up to 50%. Optimisers or microinverters can limit the effect on the rest of the panels.
Do solar panels work at night?
No. A battery can store daytime solar, or cheap overnight electricity, for the evening.
Do solar panels work in snow?
Not while they're covered. Snow usually slides off tilted panels quickly. Don't go on the roof to clear it.
Are solar panels heated to melt snow?
No. Home solar panels have no heaters. Snow melts or slides off as daylight warms the panels.
Does cold weather reduce solar output?
No, the opposite. Panels work slightly better when cold. Less output in winter is down to shorter days and lower sun.
Read next
Sources
Figures and rules on this page were checked on 11 October 2026. Schemes, tariffs and prices change, so check the latest before you decide.
- DESNZ: Feed-in Tariff load factor analysis 2024/25, 18 December 2025
- DESNZ: Energy Trends March 2026, 2 April 2026
- DESNZ: Energy Trends June 2026, 29 September 2026
- DESNZ: Digest of UK Energy Statistics 2026, chapter 6 (renewables), 2026
- Energy Saving Trust: Solar power fact check, updated 13 August 2026
- Energy Saving Trust: Solar panels, costs, savings and benefits, updated 1 October 2026
- Which?: Solar panels buying advice, 12 August 2026
- Trina Solar: Vertex S+ NEG9R.28 datasheet, 2026
- REC: Alpha Pure-RX datasheet, August 2024
- Ofgem: Energy price cap, 1 October to 31 December 2026, 26 August 2026
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