Does Rooftop Solar Work in Winter in India? Fog, Smog, Output and 7 Tips (2026)

As winter arrives, many families across India ask our SolarConnect India team the same question: "Will my rooftop solar stop working in winter, or in fog and smog?" It is one of the most common solar myths. The short answer is no. Solar panels keep generating through winter. Output changes a little with shorter days, a lower sun and haze, but cool weather actually helps panels work more efficiently. Here is what really happens and how to get the most units from your system this season.

Quick answer

Rooftop solar works in winter all over India. Daily units can be somewhat lower than in summer because days are shorter and the sun sits lower in the sky, and heavy fog or smog in North India can cut output on those particular days. On the other hand, panels lose efficiency in heat and gain it in cool weather, and with net metering your yearly savings stay balanced across seasons.

Myth: Solar panels don't work in winter

Fact: Panels run on sunlight, not heat. As long as there is daylight, they produce electricity. Winter skies in much of central, western and southern India are often clear and dry, which can give good generation. Even on overcast days the system keeps producing, only less. Read our top 10 solar myths in India for more myths and facts.

Why cold weather can help solar panels

Every solar panel datasheet lists a "temperature coefficient", which shows how much power is lost for each degree above 25°C cell temperature. For common crystalline panels this is usually around -0.3% to -0.45% per °C. On a hot summer roof, cells can run far above 25°C and lose noticeable power. In winter, cells stay cooler, so each hour of sunlight is converted more efficiently. Modern TOPCon and bifacial panels generally have better temperature coefficients; see bifacial vs TOPCon panels explained.

What actually reduces winter output

• Shorter days: fewer sunlight hours mean fewer units per day.
• Lower sun angle: the sun travels lower in the southern sky, so shadows from water tanks, parapet walls, trees and nearby buildings get longer.
• Fog and smog: in the Indo-Gangetic plain (Punjab, Haryana, Delhi, Uttar Pradesh, Bihar and parts of West Bengal), dense fog and smog mornings reduce sunlight reaching the panels.
• Dust and pollution on the glass: dry winter air and smog leave a fine layer on panels that blocks light.

How much each factor matters depends on your city, roof and system. Our guide on how many units a 1 kW system produces per day explains the yearly average, which already includes seasonal ups and downs.

7 tips to get more units from rooftop solar in winter

1. Check for new shadows. Walk your roof around 10 AM and 2 PM. Anything casting a shadow on the panels in winter costs units, because one shaded panel can pull down the whole string.
2. Clean when dust or smog builds up. Use plain water and a soft cloth or mop, early morning or evening. No detergent or hard brushes. See safe solar panel cleaning methods.
3. Clear dew and fog residue gently. Morning dew dries on its own, but if it leaves dusty streaks, a light rinse helps.
4. Use heavy appliances in daylight. Run the washing machine, water pump, geyser and iron between 10 AM and 3 PM, when panels produce the most.
5. Watch your inverter app or display. Compare this week's units with the same week last year, not with May or June.
6. Don't change tilt yourself. Structures are designed for a fixed tilt close to your latitude. Adjusting them without a technician can damage mounts or void warranty.
7. Book a check if output falls suddenly. A sudden drop is usually a fault, loose connection or shading, not winter. Read 9 things to check when solar produces less.

Does net metering cover the winter dip?

Yes. With an on-grid system, extra units you export on sunny days are credited against units you import later, according to your state DISCOM's net metering rules and settlement period. That is why solar savings are best judged over a full year, not one winter month. Learn more in our net metering guide.

Is winter a good time to install rooftop solar?

Yes. Winter is comfortable for rooftop work in most of India, and installing before summer means you are ready for the months of highest generation and highest electricity bills. Under PM Surya Ghar: Muft Bijli Yojana, eligible homes with DCR panels can get Rs 30,000 per kW for the first 2 kW and Rs 18,000 for the 3rd kW, up to Rs 78,000. Check the details in our PM Surya Ghar 1 kW, 2 kW and 3 kW subsidy guide.

Frequently asked questions

Do solar panels work on foggy days?

Yes, but output is lower because fog blocks part of the sunlight. Generation usually improves once the fog lifts later in the day.

Do solar panels work better in cold weather?

Panels convert light more efficiently when they are cool, so a clear, cold day can be very productive. Fewer daylight hours in winter can still mean fewer total units than in summer.

Should I buy a battery for winter?

Not just for winter. A battery is useful if you face regular power cuts or want backup at night. For most homes, an on-grid system with net metering is enough.

Talk to the SolarConnect India team

Planning rooftop solar or a solar dealership in your area? Our team handles site survey, system design, installation and PM Surya Ghar subsidy paperwork through our empanelled partner. Call us on +91 92823 67700 (WhatsApp) or 033 3183 5203, or explore how a pan-India solar dealership with SolarConnect works.