Yes — solar panels generate electricity even in cloudy conditions, just at reduced output (10–25% of peak capacity). The UK's diffuse light is sufficient for a worthwhile annual yield.
🏠Homeowner view
Solar panels work whenever there is daylight — they don't need direct sunshine. In cloudy conditions, they generate at reduced output — typically 10–25% of their peak rated capacity on overcast days. But even in the UK's famously grey weather, solar panels are worthwhile. The UK receives enough annual sunshine (around 1,000–1,600 hours per year depending on location) to make solar financially viable. In fact, Germany — which has less sunshine than the UK — is one of the world's largest solar markets. What matters is the annual total of daylight and diffuse light, not just the sunny days. The output of your panels varies significantly: a bright summer day might give you 90–100% of rated output; a bright but hazy day might give 60–70%; a dull overcast day might give 10–20%; and panels still generate a small amount even in light rain. The seasonal variation is significant — you'll generate much more in summer (May–August) than in winter.