Yes. Solar panels generate electricity from daylight, not just direct sunshine, so they keep producing under grey skies. In West Yorkshire a 4kW system on a south-facing roof makes about 3,826kWh a year according to the European Commission's PVGIS model, and even in December it still produces around 127kWh. Cloud lowers output on the day; it does not switch the panels off. This guide sets out what a Yorkshire system really makes each month, why winter output falls, and what makes the biggest difference to how much you generate.
Daylight, not sunshine
A solar panel turns light into electricity through the photovoltaic effect. Direct sunlight gives the most energy, but on an overcast day a large share of the light still reaches the ground as diffuse light, scattered through the cloud rather than blocked by it. Panels respond to that diffuse light, which is why a bright overcast day still produces a useful amount of power and only near-darkness brings output close to zero.
A simple test: if a room is bright enough to read in without switching the light on, your panels are generating. The amount drops as the cloud thickens, but the system goes on working through the day.
What a West Yorkshire system makes, month by month
The table below shows PVGIS's estimate for a 4kW system near Wakefield, facing due south on a 35 degree roof with typical system losses. It already includes the cloud cover recorded for the area, so it reflects a normal Yorkshire year rather than a sunny best case.
| Month | Output (kWh) | Share of the year |
|---|---|---|
| January | 132 | 3% |
| February | 205 | 5% |
| March | 335 | 9% |
| April | 431 | 11% |
| May | 479 | 13% |
| June | 447 | 12% |
| July | 472 | 12% |
| August | 433 | 11% |
| September | 353 | 9% |
| October | 245 | 6% |
| November | 167 | 4% |
| December | 127 | 3% |
| Year | 3,826 | 100% |
May and July are the strongest months at close to 480kWh each. December and January sit near 130kWh, about a quarter of the summer peak, and the six months from April to September produce roughly two-thirds of the year's electricity.
Why winter output falls
The winter dip is driven mostly by the calendar rather than the weather. In late December West Yorkshire gets around seven and a half hours of daylight and the sun stays low, so each square metre of panel receives far less energy than in late June, when daylight runs to around seventeen hours. Cloud makes the difference between a good and a poor day within a season, but day length and sun height decide the size of the seasons themselves.
That is why a system sized for a Yorkshire home is planned around the whole year. Our guide to how many solar panels you need works from annual use rather than a single summer week.
Cool, bright days can beat hot ones
Solar panels are slightly more efficient when they are cool. Cell voltage falls as panel temperature rises, so on a very hot day a panel converts a smaller share of the light that reaches it. A clear, cool day in March or September can therefore deliver output close to midsummer for the same amount of light, and the mild Yorkshire climate works in the panels' favour for much of the year.
Roof direction matters more than cloud
For the same 4kW system near Wakefield, PVGIS gives about 3,826kWh a year facing south, about 3,021kWh facing east and about 2,985kWh facing west. That is roughly a fifth less for an east or west roof, a bigger gap than the difference between a sunny and a cloudy year. East-west layouts are still widely used: they produce earlier and later in the day, which suits homes that use most of their power in the morning and evening.
Local figures for two Five Towns roofs are on our solar panels Wakefield and solar panels Castleford pages.
Shading costs more than cloud
Cloud reduces light evenly across the whole array. A shadow from a chimney, a tree or a neighbouring building falls on part of it, and in a simple string system one shaded panel can pull down the output of the panels wired with it. That is why shading is checked at survey, panel positions are chosen to avoid the worst of it, and power optimisers or microinverters are used where some shading cannot be avoided, so each panel contributes what it can.
Rain, snow and dirt
Rain does no harm and helps rinse dust off tilted panels, which is one reason panels on a pitched UK roof rarely need regular cleaning. Snow stops generation while it covers the glass, but it usually slides off a pitched roof within a day or two of the sun returning. A light coating of dust or pollen makes a small difference; bird droppings or moss on one panel matter more because they behave like shading.
Making the most of cloudy-day output
On grey days a system produces less, so more of what it makes is used in the house as it is generated. On bright spring and summer days it often makes more than the home needs, and that surplus is where a battery earns its place: it stores the daytime excess for the evening rather than exporting it. Our battery storage page covers sizing, and our guide to home battery performance in winter explains what to expect between November and February.
Is Yorkshire too cloudy for solar?
No. A 4kW south-facing system near Wakefield produces about 3,826kWh in an average year, cloud included. The figures are lower than southern Europe, but the panels are rated on annual output in UK conditions, not on sunny days. If you are weighing it up for your own roof, our solar panel installation page explains how a system is surveyed, designed and connected, and solar panels and batteries on homes carry 0% VAT until 31 March 2027. For homes across the district, see Bradford solar panel installation as well as the Wakefield and Castleford pages above.
Frequently asked questions
Do solar panels work on cloudy days?
Yes. They generate from daylight, including the diffuse light that passes through cloud. Output is lower than on a bright day but does not fall to zero until it is close to dark.
How much does a solar system produce in a Yorkshire winter?
PVGIS puts a 4kW south-facing system near Wakefield at about 132kWh in January and 127kWh in December, around a quarter of the May and July figures.
Do solar panels work when it rains?
Yes, at reduced output, and rain helps keep tilted panels clean.
Is an east or west facing roof worth it in the UK?
Often, yes. PVGIS gives about a fifth less annual output than due south near Wakefield, and the generation shifts towards the morning or evening.