Peak sun hours in Michigan
Michigan averages 3.8 peak sun hours a day across the year, 47th of the 50 states. At that figure a 400-watt panel produces about 1.17 kWh a day after real-world losses, and covering the 900 kWh average US bill takes about 26 panels. Detroit, the state's biggest city, runs slightly ahead of the statewide figure at 3.9 hours; treat 3.8 as the midpoint of a real spread rather than a local reading.
cloudy-country sun: 3.8 of a possible ~6.5 hours
Panel counts for Michigan bills
Computed at Michigan's 3.8 hours with 400W panels and the 0.77 derate; the US-average column shows what the same bill takes at 4.5 hours, so you can see what your state's sun is worth in hardware.
| Monthly usage | Michigan | System size | US average |
|---|---|---|---|
| 500 kWh/mo | 15 panels | 6 kW | 12 panels |
| 750 kWh/mo | 22 panels | 8.8 kW | 18 panels |
| 900 kWh/mo | 26 panels | 10.4 kW | 22 panels |
| 1,000 kWh/mo | 29 panels | 11.6 kW | 24 panels |
| 1,500 kWh/mo | 43 panels | 17.2 kW | 36 panels |
| 2,000 kWh/mo | 57 panels | 22.8 kW | 48 panels |
What 3.8 hours means in practice
Michigan is at the cloudy end of the table: 47th of 50 at 3.8 peak sun hours, 16% under the national average. Covering the 900 kWh average bill takes 26 panels here against 22 nationally. Solar still works at this latitude and cloud cover, and panels run cooler here, which claws a little of it back.
How a Michigan year is shaped
The 3.8-hour figure is an annual average, and no month is average. These are the twelve monthly means for Michigan from NASA's 2001-2020 solar climatology, each as a share of the state's own annual mean, with that share applied to the 3.8-hour planning figure. July and December are marked.
| Month | Share of the annual average | Peak sun hours (est.) |
|---|---|---|
| January | 36% | 1.4 |
| February | 60% | 2.3 |
| March | 96% | 3.6 |
| April | 126% | 4.8 |
| May | 151% | 5.7 |
| June | 168% | 6.4 |
| July | 170% | 6.5 |
| August | 144% | 5.5 |
| September | 111% | 4.2 |
| October | 68% | 2.6 |
| November | 41% | 1.5 |
| December | 28% | 1.1 |
Michigan runs a short, hard solar year. July reaches 170% of the annual average and December falls to 28%, 6 to one, with 53% of the light arriving in four months. In hours that is 6.5 a day at the July top against roughly 1.1 in December. Sizing a Michigan array off the annual figure alone is fine on the grid and badly wrong off it.
Half the Michigan calendar sits above the annual average and half below: April through September are the six months that beat it, carrying 72% of the year's light. April is already worth about 4.8 hours a day, so the productive half of the year starts earlier than most people expect.
Michigan homes are light users by national standards, 618 kWh a month on EIA's 2024 average against 863 nationally, 28% below. That is only 18 panels at the annual figure, which is why modest arrays go a long way here. Carrying the same house through December on its own would take 62, 3.4 times more.
Michigan is more uniform than most. The 16 grid cells sampled across the state span 10%, sunniest in the southeast and dimmest in the northwest, which scales to about 4.0 hours against 3.6. Enough to notice on a production estimate, not enough to change which system you buy. Detroit sits inside that band, not at the edge of it.
What that sun is worth on a Michigan bill
| EIA, 2024 residential averages | Michigan | United States |
|---|---|---|
| Average home's monthly use | 618 kWh | 863 kWh |
| Price per kilowatt-hour | 19.3¢ | 16.48¢ |
| Average monthly bill | $119.31 | $142.26 |
| One 400W panel, a year's output | 427 kWh | 506 kWh |
| What that output displaces | $82 | $83 |
Michigan pays 19.3¢ a kilowatt-hour, 12th highest in the country and 17% over the national 16.48¢. A single 400-watt panel therefore displaces about $82 of electricity a year here. Prices above the national line do more for a solar case than an extra half hour of sun does, because the sun sets the numerator and the rate sets what it is worth.
Which is why the sun ranking undersells Michigan. It places 47th of fifty for sunlight and 20th for what a panel actually earns, a jump of 27 places, and the second number is the one that shows up on a bill. Compare it with a state that gets similar sun: Washington gets the same sun (3.8 hours to Michigan's 3.8) and pays 11.9¢ against 19.3¢, so one panel is worth about $32 more a year in Michigan than in Washington.
Two warnings on those dollar figures. They are displaced electricity and nothing else: no install cost, no incentive, no financing, and no assumption about how your utility settles a surplus, which is the single biggest unknown in the sum. And a state average hides the utility you are actually on; 19.3¢ is every Michigan residential customer averaged together, and neighbouring territories can differ by more than the gap between two states in the ranking.
Getting a number for your address
For a location-exact figure, run your address through NREL's free PVWatts; it uses measured weather for your grid cell and will also model roof tilt and direction, which statewide numbers cannot. Then compare its annual kWh against a quote's promise before you sign anything.
Questions people ask
How many solar panels do I need in Michigan?
About 26 400-watt panels (10.4 kW) for the 900 kWh a month an average US home uses, at Michigan's 3.8 peak sun hours. For the average Michigan home specifically, which EIA measured at 618 kWh a month in 2024, it is 18. Your own bill is the variable that matters, and the calculator takes any figure.
Is 3.8 peak sun hours good for solar?
It is below the 4.5-hour national average but far from disqualifying. Panel counts run about 18% higher here for the same bill, and the December trough measured above deserves respect in any off-grid plan. Grid-tied systems ride through it on net metering.
How much is one solar panel worth a year in Michigan?
About $82. One 400-watt panel at Michigan's 3.8 peak sun hours makes roughly 427 kWh a year after the 0.77 derate, and Michigan residential electricity averaged 19.3¢ a kilowatt-hour in 2024 (EIA), which puts Michigan 20th of the 50 states on this measure against 47th on sunlight alone. That figure is displaced electricity only. It says nothing about install cost, incentives, or how your utility settles a surplus.
Do peak sun hours change with the seasons in Michigan?
Yes, by a factor of 6 here. NASA's 2001-2020 climatology puts Michigan's July at 170% of the annual average and December at 28%, so the 3.8-hour figure on this page is the midpoint of a curve running from roughly 6.5 hours a day down to 1.1. Grid-tied homes bank the summer surplus as credit; off-grid designs have to size for the trough, and in Michigan that means 62 panels for an average local bill instead of 18.