Maryland Solar Panel Performance Benchmarks

A 6kW solar system in Maryland produces between 7,740 and 8,400 kWh per year depending on location. The Baltimore metro area averages about 8,160 kWh for a 6kW system. The Eastern Shore near Salisbury runs higher at around 8,400 kWh due to slightly clearer air and lower humidity inland. Western Maryland near Cumberland produces about 7,740 kWh, the lowest in the state, due to mountain terrain and higher cloud frequency. The DC suburbs of Montgomery and Prince George's Counties average roughly 8,100 kWh.

Monthly Production Benchmarks: Maryland 6kW Reference System

Expected monthly production for a south-facing, 30-degree tilt, 6kW system. Derived from pvlib simulation using Open-Meteo ERA5 historical weather data, Baltimore as the statewide reference location.

Month	Expected Production (kWh)	Notes
January	360	Short winter days
February	490	Modest recovery
March	690	Spring ramp begins
April	840	Strong shoulder month
May	930	Near-peak
June	950	Peak production
July	940	Heat and humidity present
August	900	Late summer, still strong
September	760	Fall transition
October	600	Seasonal decline
November	420	Winter approach
December	330	Lowest month
Annual Total	~8,210	Baltimore-area 6kW reference

(Source: pvlib physics modeling, Open-Meteo ERA5 weather data)

Annual Benchmarks by System Size and Maryland Region

System Size	DC Suburbs (Montgomery / PG)	Baltimore Metro	Annapolis Area	Eastern Shore (Salisbury)	Western MD (Cumberland)
4 kW	5,400	5,440	5,480	5,600	5,160
6 kW	8,100	8,160	8,220	8,400	7,740
8 kW	10,800	10,880	10,960	11,200	10,320
10 kW	13,500	13,600	13,700	14,000	12,900
12 kW	16,200	16,320	16,440	16,800	15,480

DC Suburbs specific yield: ~1,350 kWh/kW/year. Baltimore: ~1,360. Annapolis: ~1,370. Eastern Shore: ~1,400. Western MD: ~1,290.

(Source: pvlib physics modeling, Open-Meteo ERA5 weather data, 2015–2024 averages)

Maryland Climate Zones and Performance Ratio Targets

Maryland is one of the more compact states but spans meaningful climate variation from the Allegheny highlands in the west to the Chesapeake Bay tidewater in the east. Performance ratios below 0.77 in any Maryland region warrant investigation.

Climate Zone	Representative Area	Annual Specific Yield	Expected PR Range
DC Suburbs / Inner Piedmont	Rockville, Silver Spring, College Park, Bowie	1,330–1,370 kWh/kW	0.77–0.85
Baltimore Metro / Central MD	Baltimore city, Towson, Columbia, Annapolis	1,350–1,390 kWh/kW	0.78–0.86
Eastern Shore	Salisbury, Cambridge, Easton, Ocean City area	1,380–1,420 kWh/kW	0.78–0.86
Western Maryland	Cumberland, Hagerstown, Garrett County	1,250–1,310 kWh/kW	0.75–0.83

Learn more about how these benchmarks are calculated at /resources/methodology.

What Affects Maryland Solar Output

• Chesapeake Bay temperature moderation: The bay moderates temperatures across central Maryland, keeping summer days cooler and winter nights milder than inland Pennsylvania or Virginia. Cooler summer temperatures slightly improve panel efficiency relative to states further south.
• Eastern Shore irradiance advantage: The Eastern Shore receives marginally higher direct normal irradiance than the Baltimore metro, partly from lower aerosol concentrations and slightly clearer Atlantic air. The 3% annual yield advantage over Baltimore is small but consistent and shows up in ERA5 data.
• Western Maryland mountain terrain: Garrett County and the Allegheny highlands receive significantly more cloud cover, more annual snowfall, and stronger orographic weather effects than the rest of the state. Western MD averages about 10% less annual production than the Eastern Shore. Snow accumulation on panels from November through March is a seasonal factor that requires monitoring.
• DC urban heat island: Montgomery and Prince George's Counties adjacent to Washington DC experience elevated ambient temperatures in summer, raising panel operating temperatures and suppressing peak output by 1–3%. This is distinct from shading or soiling and is a background factor in any DC suburb benchmark.
• SREC market: Maryland's 50% Renewable Portfolio Standard target by 2030 has driven a robust Solar Renewable Energy Credit market. SREC prices and net metering rules are important inputs to any Maryland financial model and are set by the Maryland Public Service Commission.

Frequently Asked Questions

Q: What should a 6kW solar system produce per month in Baltimore?

A: The Baltimore benchmark averages about 683 kWh/month. June is the peak at roughly 950 kWh; December is the lowest at 330 kWh. Consistent summer production below 800 kWh/month (June-August) on a 6kW system in Baltimore suggests a problem worth investigating.

Q: Is solar worth it in Maryland given the cloudy winters?

A: Yes. Maryland's summer production months are strong, and winter lows are partially offset by high SREC prices, net metering credits, and the federal investment tax credit. A Baltimore 6kW system producing 8,160 kWh/year is comparable to what a similar system produces in New Jersey, which has one of the most mature solar markets in the country.

Q: Why does a Western Maryland system produce so much less than an Eastern Shore system?

A: Cumberland-area systems average about 7,740 kWh/year for 6kW versus 8,400 kWh/year near Salisbury. The 8% gap reflects more mountain cloud cover, higher elevation, and greater snowfall in Western MD. Both systems performing at their regional benchmark are healthy.

Q: How do I get an independent benchmark for my Maryland solar system?

A: A valid benchmark requires production data and actual hourly weather at your address. Maryland's east-to-west variation is large enough that a single statewide average is misleading for individual system diagnosis. ERA5 weather data captures this regional variation accurately. Learn more at /resources/methodology.

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Data: pvlib physics modeling + Open-Meteo ERA5 weather data | Last updated: 2026-04-08 | Solar Benchmark