Peak sun hours in Maryland
Maryland averages 4.2 peak sun hours a day across the year, 33rd of the 50 states. At that figure a 400-watt panel produces about 1.29 kWh a day after real-world losses, and covering the 900 kWh average US bill takes about 23 panels. Baltimore, the state's biggest city, runs slightly ahead of the statewide figure at 4.3 hours; treat 4.2 as the midpoint of a real spread rather than a local reading.
modest sun: 4.2 of a possible ~6.5 hours
Panel counts for Maryland bills
Computed at Maryland's 4.2 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 | Maryland | System size | US average |
|---|---|---|---|
| 500 kWh/mo | 13 panels | 5.2 kW | 12 panels |
| 750 kWh/mo | 20 panels | 8 kW | 18 panels |
| 900 kWh/mo | 23 panels | 9.2 kW | 22 panels |
| 1,000 kWh/mo | 26 panels | 10.4 kW | 24 panels |
| 1,500 kWh/mo | 39 panels | 15.6 kW | 36 panels |
| 2,000 kWh/mo | 51 panels | 20.4 kW | 48 panels |
What 4.2 hours means in practice
Maryland runs 7% below the national solar average, 33rd of 50 at 4.2 hours. That is workable sun, not bad sun: the 900 kWh bill takes 23 panels here versus 22 nationally, 1 more. Germany built the world's densest solar fleet on worse.
How a Maryland year is shaped
The 4.2-hour figure is an annual average, and no month is average. These are the twelve monthly means for Maryland from NASA's 2001-2020 solar climatology, each as a share of the state's own annual mean, with that share applied to the 4.2-hour planning figure. June and December are marked.
| Month | Share of the annual average | Peak sun hours (est.) |
|---|---|---|
| January | 51% | 2.1 |
| February | 71% | 3.0 |
| March | 95% | 4.0 |
| April | 122% | 5.1 |
| May | 137% | 5.7 |
| June | 152% | 6.4 |
| July | 150% | 6.3 |
| August | 132% | 5.5 |
| September | 107% | 4.5 |
| October | 79% | 3.3 |
| November | 58% | 2.4 |
| December | 44% | 1.9 |
The gap between Maryland's best month and its worst is 3.4 to one: June at 152% of the annual average, December at 44%, or about 6.4 hours a day against 1.9. Four months carry 48% of the year's light. A grid-tied system rides that out on net metering without anyone noticing.
Half the Maryland calendar sits above the annual average and half below: April through September are the six months that beat it, carrying 67% of the year's light. April is already worth about 5.1 hours a day, so the productive half of the year starts earlier than most people expect.
Bills here run above the national line. The average Maryland household used 929 kWh a month in 2024 against 863 nationally, 8% more, and covering that across a year takes 24 panels at Maryland's sun. Covering it from December sun alone would take 54, 2.3 times the array, which is the number that decides whether a battery plan is realistic.
Maryland is more uniform than most. The 4 grid cells sampled across the state span 7%, sunniest in the south and dimmest in the northwest, which scales to about 4.3 hours against 4.1. Enough to notice on a production estimate, not enough to change which system you buy. Baltimore sits inside that band, not at the edge of it.
What that sun is worth on a Maryland bill
| EIA, 2024 residential averages | Maryland | United States |
|---|---|---|
| Average home's monthly use | 929 kWh | 863 kWh |
| Price per kilowatt-hour | 17.86¢ | 16.48¢ |
| Average monthly bill | $165.87 | $142.26 |
| One 400W panel, a year's output | 472 kWh | 506 kWh |
| What that output displaces | $84 | $83 |
At 17.86¢ a kilowatt-hour Maryland sits 8% above the national 16.48¢, 13th of the fifty states on price. One 400-watt panel offsets roughly $84 of Maryland power a year. Mid-table on rates means the project lives or dies on the quote and the net-metering terms rather than on either the sun or the tariff.
Which is why the sun ranking undersells Maryland. It places 33rd of fifty for sunlight and 16th for what a panel actually earns, a jump of 17 places, and the second number is the one that shows up on a bill. Compare it with a state that gets similar sun: Rhode Island gets less sun (4.1 hours to Maryland's 4.2) and pays 28.65¢ against 17.86¢, so one panel is worth about $48 less a year in Maryland than in Rhode Island.
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; 17.86¢ is every Maryland 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 Maryland?
About 23 400-watt panels (9.2 kW) for the 900 kWh a month an average US home uses, at Maryland's 4.2 peak sun hours. For the average Maryland home specifically, which EIA measured at 929 kWh a month in 2024, it is 24. Your own bill is the variable that matters, and the calculator takes any figure.
Is 4.2 peak sun hours good for solar?
It is below the 4.5-hour national average but far from disqualifying. Panel counts run about 7% 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 Maryland?
About $84. One 400-watt panel at Maryland's 4.2 peak sun hours makes roughly 472 kWh a year after the 0.77 derate, and Maryland residential electricity averaged 17.86¢ a kilowatt-hour in 2024 (EIA), which puts Maryland 16th of the 50 states on this measure against 33rd 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 Maryland?
Yes, by a factor of 3.4 here. NASA's 2001-2020 climatology puts Maryland's June at 152% of the annual average and December at 44%, so the 4.2-hour figure on this page is the midpoint of a curve running from roughly 6.4 hours a day down to 1.9. Grid-tied homes bank the summer surplus as credit; off-grid designs have to size for the trough, and in Maryland that means 54 panels for an average local bill instead of 24.