How Solar Panels Perform in Winter: Real UK Data

The most common question about solar panels in the UK is whether they generate anything useful in winter. The honest answer: less than summer, but more than you'd think. And the economics still work.

Actual monthly generation

Here's real data from a 4kW south-facing system in the East Midlands (averaged over three years):

December and January together account for about 6.7% of annual output. That's not nothing - it's 250 kWh, worth about £60 at current rates. But it's clearly less productive than the May-August peak where 50% of annual generation occurs.

Why winter generation still matters

Self-consumption is higher in winter. In summer, you generate more than you can use and export the surplus at 12-15p/kWh. In winter, nearly everything you generate gets used directly, saving you 24p/kWh. The value per kWh generated is actually higher in winter.

Daylight hours, not sunshine. Solar panels generate from daylight, not direct sun. A cloudy December day still produces 5-15% of rated output. Panels on short winter days generate from around 8am to 4pm.

Snow is rarely a problem. UK snowfall typically melts within hours on roof-mounted panels, which sit at an angle and generate some heat even in low light. Persistent snow cover (rare in most of England) can be brushed off.

The seasonal payback calculation

Many people calculate payback using average annual figures. That's correct - the annual savings of £800-950 account for the seasonal variation. You don't need to worry about winter specifically; the summer surplus more than compensates.

If winter output concerns you, adding battery storage helps you capture more value from every kWh generated. And pairing solar with a time-of-use tariff means you benefit from cheap overnight electricity during darker months.

Optimising for winter

A few things improve winter performance:

• Panel angle: Steeper angles (40-50 degrees) capture more low-angle winter sun. Most UK roofs are 30-40 degrees, which is a good all-year compromise.
• Keep them clean: Without summer rain, panels can accumulate grime. A winter rinse helps.


• East-west split: Systems facing east and west generate more evenly throughout shorter days than south-facing systems that peak briefly at midday.