Do solar panels actually work in British weather?
Yes. Measured across 115 UK cities, a median British roof receives about 993 usable sun hours a year — enough for a 4 kW array to produce roughly 3,376 kWh, more than a typical household uses.
Panels need daylight, not heat
Solar panels generate from light, and they are slightly more efficient in cool conditions than in high heat. Britain's problem is cloud and short winter days, not temperature. A bright overcast day still produces meaningful output — considerably less than full sun, but far from nothing.
What the measurements show
The spread across Britain is narrower than people expect: 1,186 hours in Penzance against 759 in Inverness. That is a 1.56× difference across the whole country. For comparison, the range across the cities we have measured in North America is more than twice as wide.
| City | Sun hrs | 4 kW output | Payback |
|---|---|---|---|
| Penzance | 1,186 | 4,032 | 10.3 yrs |
| Hastings | 1,148 | 3,903 | 10.5 yrs |
| Truro | 1,144 | 3,890 | 10.6 yrs |
| Merthyr Tydfil | 993 | 3,376 | 12.2 yrs |
| Derry/Londonderry | 785 | 2,669 | 15.3 yrs |
| Inverness | 759 | 2,581 | 15.7 yrs |
The real British constraint is seasonal, not annual
Annual totals hide the shape of the year. British output is heavily concentrated in summer, and the winter months — when heating demand is highest — produce a small fraction of the annual total. Every individual city page on this site shows its own month-by-month breakdown, calculated from solar geometry at that latitude.
Shading matters too, though less than many expect: across our UK measurements the median roof loses only a few percent of its potential to trees, chimneys and neighbouring buildings.
Sunlight figures are our own measurements: the median of roughly 16 suburban rooftop samples per city from Google's Solar API, across 115 UK cities. Electricity price is the Ofgem default tariff cap unit rate, 26.11p/kWh, for 1 July – 30 September 2026 — the cap is reset on 1 October 2026 and will be restated excluding VAT, so this figure has a known expiry. Household usage is Ofgem's Typical Domestic Consumption Value of 2,500 kWh, revised down on 1 July 2026. Export is modelled at a conservative 12p/kWh. Estimates only — not a quote, and not financial advice.
Check a specific UK city
Frequently asked
Do solar panels work on cloudy days in the UK?
Yes, at reduced output. Panels generate from daylight rather than direct sun, so a bright overcast day still produces meaningfully — typically a fraction of full-sun output but far from zero. Our sunlight figures are already usable hours, with cloud and shading accounted for, not hours of daylight.
Is the UK too far north for solar?
No. A median UK roof gets about 993 usable sun hours a year, enough for a 4 kW array to out-produce a typical household's 2,500 kWh. Germany, at a similar latitude, has one of the world's largest installed solar bases. Northern Scotland is genuinely marginal; most of Britain is not.
Do solar panels work in winter in the UK?
They work, but produce far less. British output concentrates heavily in summer, and the darkest months yield a small fraction of the annual total — awkward, because that is when heating demand peaks. Every city page here shows its own monthly breakdown so you can see the shape rather than an annual average.