How much electricity do solar panels produce in December?

A typical 4kW system in the UK produces around 80–120 kWh in December. This is roughly 20% of peak summer output, but still enough to make a meaningful dent in your electricity bill.

Should I get a battery to use winter solar at night?

A battery helps you use more of your winter solar generation by storing daytime electricity for evening use. Without a battery, any solar you don't use during the day is exported to the grid at around 4.5p/kWh. With a battery, you can use it yourself and save 24.5p/kWh instead.

Do solar panels work in Scotland during winter?

Yes, but output is lower than in southern England. Scotland gets fewer daylight hours and lower solar irradiance in winter. A 4kW system in Glasgow might produce 60–90 kWh in December compared to 100–120 kWh in London. Annual totals are 10–15% lower overall.

Is it worth installing solar panels before winter?

Yes. Installation takes 1–2 days and can happen any time of year. Installing in autumn means you're ready to capture the full spring and summer generation the following year, and you still benefit from winter output immediately.

Home Solar Guide

Do Solar Panels Work in Winter?

Q: Do solar panels work when it's overcast?

Yes. Solar panels work on daylight, not direct sun. On an overcast day they produce 10–30% of their rated capacity. Modern monocrystalline panels are particularly effective at capturing diffused light.

Last updated: 17 March 2026

Independently written

Solar panels on UK home roof backlit by sun showing clean energy generation — Solar panels still generate electricity during winter months, just at reduced output.

Do solar panels work in winter in the UK?

Yes, solar panels work in winter. UK panels typically produce 10–25% of their summer output during December and January, but they still generate meaningful electricity. A 4kW system produces around 100–150 kWh per month in winter — enough to offset a significant portion of your electricity bill.

How Much Do Solar Panels Produce in Winter?

Solar panels need daylight, not heat. Even on overcast winter days, diffused light reaches the panels and generates electricity. In fact, solar panels are slightly more efficient in cold temperatures — they lose efficiency as they get hotter in summer.

A typical 4kW system in the south of England produces approximately: - June–July: 500–550 kWh/month - December–January: 80–120 kWh/month - March–April: 300–380 kWh/month - Annual total: 3,800–4,200 kWh

Winter months account for roughly 10–15% of your annual solar generation. The remaining 85–90% comes from the longer, sunnier days between March and October.

UK solar sun path diagram showing seasonal movement for optimal panel positioning — The sun sits lower in winter, reducing the angle of light hitting your panels.

Why Solar Panels Still Work on Cloudy Days

Solar panels respond to light intensity, not direct sunshine. On a cloudy UK winter day, panels typically produce 10–30% of their rated capacity. Modern monocrystalline panels are particularly good at capturing diffused light.

The key factor is daylight hours, not cloud cover. In December, the UK gets around 7–8 hours of daylight compared to 16–17 hours in June. This shorter window is the main reason winter output drops — not the clouds themselves.

Source: PVGIS (Photovoltaic Geographical Information System), European Commission.

UK yearly solar energy production growth chart over 10 year period — Annual solar production remains consistent year over year, with predictable seasonal variation.

Does Snow Affect Solar Panels?

Snow rarely causes problems for UK solar panels. Most panels are installed at a 30–40 degree angle, which means snow slides off naturally. Even a thin layer of snow can reduce output, but the dark surface of the panels absorbs heat and accelerates melting.

Heavy snowfall is uncommon in most of the UK, and when it does occur, it typically melts within a day or two. The loss of generation from occasional snow is negligible over a full year — well under 1% of annual output.

Solar panels on a detached UK home with established garden and greenery — UK solar panels work year-round, producing the most during spring and summer months.

How to Maximise Winter Solar Output

Tips for getting the most from your panels in winter:

Keep panels clear of debris and bird droppings — clean panels capture more light
Use a solar battery to store daytime generation for evening use when bills are highest
Switch to a time-of-use tariff like Octopus Go to maximise the value of stored solar energy
Run high-energy appliances (washing machine, dishwasher) during daylight hours to maximise self-consumption
Monitor your system with an app to spot any performance issues early

Solar excess daytime energy stored in battery for evening use in UK home — A solar battery stores winter daytime generation for use during dark evenings.

Are Solar Panels Still Worth It Given Winter Output?

Absolutely. The payback calculation for solar panels accounts for year-round production, including winter. A well-sized system in the UK typically pays for itself in 8–12 years, factoring in reduced winter output.

The key insight is that solar panels earn most of their value between March and October. Winter output is a bonus, not the foundation of the business case. With current electricity prices at around 24.5p/kWh (Ofgem, Q1 2026), even modest winter generation saves real money.

Source: Ofgem Quarterly Energy Price Cap, Q1 2026.

UK solar panel cost versus savings graph showing financial returns over 25 years — Solar panels pay for themselves within 10 years and continue saving money for 25+ years.

Find out how much you could save

Answer a few questions and receive personalised solar quotes — completely free.

Start My Quote

Free, no obligation. Takes 2 minutes.

Frequently Asked Questions

Ready to see what solar could save you?

Get free, no-obligation quotes from MCS-certified installers in your area.

Get Free Quotes