Updated November 2026 by Wolf River Electric.
How much power do solar panels make on a cloudy day?
Solar panels run on light, not heat. Clouds block part of the direct sunlight, but plenty of light still gets through and scatters across the sky. Panels catch that scattered light too.
How much you lose depends on the clouds. Thin, high clouds cut output a little. A thick, dark overcast day typically drops a panel to about 10 to 25 percent of its rated output. Rain does not hurt the panels; it rinses dust and pollen off them.
Cold, clear days are often some of the best days for solar. Panels lose a little output when they get hot, about 0.3 to 0.5 percent per degree Fahrenheit above 77°F, so a bright day in March can beat a hazy day in July.
Real output from our Midwest systems, month by month
This is what Wolf River Electric customers’ systems actually made, per panel, from October 2025 to September 2026. Cloudy days are already in these numbers. September 2026 was unusually cloudy in Minnesota, and our systems there still made about 30.7 kWh per panel that month.
| Month | Minnesota (kWh per panel) | Wisconsin (kWh per panel) | Iowa (kWh per panel) |
|---|---|---|---|
| January | 14.1 | 13.6 | 24.3 |
| February | 23.1 | 25.1 | 31.4 |
| March | 34.7 | 35.4 | 41.5 |
| April | 42.1 | 44.2 | 46.6 |
| May | 56.3 | 59.4 | 57.7 |
| June | 52.2 | 53.0 | 55.1 |
| July | 55.3 | 56.2 | 59.0 |
| August | 48.2 | 47.4 | 48.5 |
| September | 30.7 | 35.0 | 30.3 |
| October | 27.4 | 31.8 | 34.2 |
| November | 17.1 | 18.3 | 23.5 |
| December | 5.4 | 6.7 | 13.3 |
| Year | 407 | 426 | 465 |
Based on 1,456 Minnesota, 202 Wisconsin and 41 Iowa Wolf River Electric systems monitored through Enphase, October 2025 to September 2026. Averages of real production from Wolf River Electric customers’ systems.
Do solar panels work in winter?
Yes, but they make much less. Short days, low sun and snow cover all cut output. Our Minnesota systems made about 5.4 kWh per panel in December, about a tenth of what they made in July. December through February together made about 10 percent of the year’s power.
That is expected and built into how we size a system. Most of a Midwest system’s power comes from April through August. For winter tips, see how to get more from solar panels in winter and what to do about snow on solar panels.
Does cloudy weather make solar a bad deal in the Midwest?
No. What matters is the yearly total, and the Midwest gets plenty of sun over a year. A typical 25-panel home system at our measured output makes about:
| State | Yearly output, 25 panels | Worth at the state’s average home electricity rate |
|---|---|---|
| Minnesota | About 10,200 kWh | About $1,670 a year (16.44 cents per kWh) |
| Wisconsin | About 10,700 kWh | About $2,030 a year (19.05 cents per kWh) |
| Iowa | About 11,600 kWh | About $1,690 a year (14.55 cents per kWh) |
Value at each state’s average home electricity rate (U.S. EIA, 2026).
Net metering and bill credits do the smoothing. Extra power from sunny summer days earns credits on your bill, and those credits cover part of what you use in cloudy or winter months. Rules vary by utility; see our Minnesota, Wisconsin and Iowa incentive guides.
Can a battery help on cloudy days?
A home battery stores solar power for the evening and keeps the lights on in an outage. It does not make more power on a cloudy day, but it lets you use more of what your panels make. Many Midwest homeowners pair a battery with solar for outage backup. See home battery backup for the Tesla Powerwall 3, Enphase and FranklinWH batteries we install.
Cloudy day solar questions
Do solar panels work when it rains?
Yes, at reduced output because of the clouds. The rain itself helps by cleaning the panels.
Do solar panels work at night?
No. At night your home uses power from the grid, your bill credits or a battery.
What happens after a week of cloudy weather?
Your home keeps running on grid power as usual. Your panels make less that week, and sunny weeks make it up over the year.
How much power does one solar panel make?
About 1.2 to 1.6 kWh a day on average in the Midwest for a 400-watt panel. See how much power a solar panel produces.
See what your roof would make
A Wolf River Electric advisor uses your roof, shade and 12 months of your bills to show what your system would make in every month, cloudy ones included. Get a free solar quote or try the free solar calculator.
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