Daylight, not sunshine
Panels respond to light. Bright, cool days are actually very good for solar, because panels work more efficiently when they're not hot. Overcast days still produce power, just less of it.
What changes through the year
- Spring and summer: long days and strong generation, often more than a household can use.
- Autumn: generation tails off but is still useful.
- Winter: short days mean much lower output. A battery on a cheap overnight tariff helps fill the gap.
What matters more than the weather
- Which way your roof faces. South is best, but east and west work well too.
- Shading from trees, chimneys and neighbouring buildings.
- How much of your own electricity you use, rather than export.
- Getting the system size right for your household.