Is it worth having solar in winter?

December is the weakest month but still generates 70-100 kWh. That's £17-£25 in savings. Over 3 winter months: £50-£75. Solar works year-round — winter is just the slow season.

Shortest Day Solar Output

By Home Solar Guide Team|Updated 19 March 2026|educational

Independently written | Evidence-based | Sources cited

Winter solstice solar — Dec 21: 2-4 kWh (London). 8hrs daylight. Still generates meaningful electricity.

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How much do solar panels generate on the shortest day?

Solar panel output on December 21 (shortest day) for a 4kW south-facing system: LONDON: Sunrise 8:04, sunset 15:53. Daylight: 7hr 49min. Peak output: ~1.2kW at noon. Total: 2.8-3.8 kWh. MANCHESTER: Sunrise 8:24, sunset 15:39. Daylight: 7hr 15min. Peak: ~0.9kW. Total: 2.0-3.0 kWh. EDINBURGH: Sunrise 8:43, sunset 15:27. Daylight: 6hr 44min. Peak: ~0.7kW. Total: 1.5-2.5 kWh. CARDIFF: Sunrise 8:17, sunset 15:56. Daylight: 7hr 39min. Peak: ~1.1kW. Total: 2.5-3.5 kWh. BELFAST: Sunrise 8:46, sunset 15:55. Daylight: 7hr 9min. Peak: ~0.8kW. Total: 1.8-2.8 kWh. WHAT IT POWERS: Dec 21 output covers: fridge (1.5 kWh/day), router (0.24), LED lighting (0.5), phone charging (0.02). The basics. It doesn't cover: electric heating, cooking, or EV charging. That's what battery + grid are for. BUT: this is the WORST day. Dec 22 gets 1 second longer. By March: 4x this output. Sources: PVGIS hourly data, Met Office sunrise/sunset times.