UK Solar Map

How much sun every part of Great Britain, Northern Ireland and Ireland actually gets, as kilowatt-hours per kilowatt of panel per year, from the European Commission's PVGIS satellite record. Type a postcode and the map turns that number into what an 800 VA plug-in kit would generate on your roof or on a balcony rail, and what it is worth.

The gap is bigger than most people expect: Eastbourne makes almost twice what the west Highlands do. Colours are relative to the layer you pick, so switch to the balcony layer before judging a north-facing flat.

Data: PVGIS v5.2, SARAH2 satellite radiation 2005–2020, 14% system loss, horizon shading from terrain. Map outline: Natural Earth. Click any cell to read it.

The first half of a postcode is enough.

Sunniest cells

    Dullest cells

      kWh per kWp a year at the optimal tilt. Postcode areas are the nearest to each grid cell.

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      How It Works

      What the colours mean

      Every cell is a quarter of a degree of latitude and longitude, about 28 by 16 km, and its number is the electricity one kilowatt of crystalline panels would make in a year in that cell: the specific yield, in kWh per kWp. It comes from PVGIS, the European Commission's photovoltaic geographical information system, which takes fifteen years of satellite-measured sunlight (SARAH2, 2005 to 2020), applies the temperature and wind from ERA5 weather reanalysis, subtracts shading from the surrounding terrain, and then takes off 14% for the cables, the inverter and dirt on the glass. It is the same source that the savings calculator's regional figures were checked against.

      The three layers are three ways of mounting the same panel. A south-facing roof at 35° is the standard UK pitch and sits within 1% of the optimal tilt everywhere in the country (the optimal angle is 38° to 41°). A vertical panel on a south-facing balcony rail or wall makes 72% of the roof figure on average, which is the number to use for a plug-in kit hung on a railing. PVGIS gives that ratio a narrow spread, 0.71 to 0.73 across all six regions, so it is not a guess.

      What the country looks like

      RegionOptimal tilt35° south roofVertical south balconyRange across the region
      South England1,0541,051754970 – 1,168
      Midlands1,0091,005737830 – 1,114
      Wales940938670828 – 1,088
      North England926923676678 – 1,054
      Northern Ireland872870637779 – 964
      Scotland797794581604 – 985

      kWh per kWp per year, the mean of every land cell in the region. Regions are drawn by latitude and longitude boxes, so the borders are approximate.

      Worked example

      An 880 W kit with an 800 VA inverter on a south-facing balcony rail in the LE8 cell south of Leicester (1,020 kWh per kWp at optimal tilt, 747 vertical) makes about 651 kWh a year after 1% clipping. At 25.7p a unit and 60% used in the home that is £100 a year, and the 260 kWh the house does not use goes to the grid unpaid. The same kit on a 35° roof in the same cell makes 885 kWh and saves £136. Moving it from the railing to the roof is worth more than moving it to Cornwall.

      These are long-run averages. A single year can sit 10% either side, and a chimney or a neighbour's gable moves the balcony figure far more than the postcode does. The plug-in solar savings calculator takes shading and orientation as inputs.

      Frequently Asked Questions

      Where in the UK gets the most sun for solar panels?

      The south coast, from Cornwall along to Kent. In the PVGIS record the best cells are around Eastbourne, the Isle of Wight, the New Forest, Rye and Salcombe, at 1,130 to 1,170 kWh per kWp a year at the optimal tilt. The dullest are the wet, mountainous west Highlands around Fort William and Loch Ness at 600 to 670, so the country spans nearly a factor of two.

      How much does an 800W plug-in kit generate in the UK?

      On a south-facing 35° roof, roughly 690 kWh a year in Scotland, 800 in the north of England, 870 in the Midlands and 910 on the south coast, for an 880 W panel set with an 800 VA inverter. Hung vertically on a south-facing balcony rail those figures fall to about 72% of that: 500 to 660 kWh. The map gives your own cell.

      Why is a vertical balcony panel so much worse than a roof?

      A vertical south-facing panel faces the low winter sun well but loses most of the high summer sun, which is where the year's energy is. PVGIS puts the vertical yield at 71% to 73% of the roof yield everywhere in the UK. It also spreads generation more evenly through the year, which suits a plug-in kit whose output is only worth anything when someone is home to use it.

      How much does solar output vary through the year in the UK?

      A lot. Averaged over the country, December makes 24 kWh per kWp and May 120, a five-to-one swing. June and July are slightly below May because of cloud and panel temperature. The month buttons on the map recolour it for any single month, and the panel shows hours of daylight beside each month's figure.

      Is this the same as a solar irradiance map?

      Nearly. An irradiance map shows the sunlight arriving, in kWh per square metre. This map shows what a panel makes of it, in kWh per kWp, after tilt, temperature, terrain shading and system losses. For a buying decision the second number is the useful one, and for the UK it runs at about 78% of the irradiance on the tilted plane.

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