Colorado Solar Panel Performance Benchmarks

Last updated: 2026-04-08 · Solar Benchmark

Colorado Solar Panel Performance Benchmarks

A correctly installed 6 kW south-facing system at 30-degree tilt in Denver produces approximately 10,080 kWh per year, equal to a specific yield of 1,680 kWh/kW/year. Grand Junction on the western slope reaches roughly 1,840 kWh/kW/year due to lower latitude relative to its position and an exceptionally dry, clear-sky climate. Mountain resort areas like Aspen and Vail fall to about 1,580 kWh/kW/year due to heavy winter snowpack and increased weather variability.

Monthly Production Benchmarks

Reference system: 6 kW, south-facing, 30-degree tilt, Denver (39.7°N, elevation 5,280 ft). Source: pvlib physics modeling, Open-Meteo ERA5 weather data.

Month	Est. Production (kWh)	Daily Average (kWh/day)
January	550	17.7
February	680	24.3
March	880	28.4
April	980	32.7
May	1,060	34.2
June	1,120	37.3
July	1,090	35.2
August	1,030	33.2
September	900	30.0
October	740	23.9
November	560	18.7
December	490	15.8
Annual Total	10,080	27.6

Note: Actual production varies with panel brand, shading, soiling, and inverter efficiency. Denver's high altitude boosts irradiance roughly 6-8% above sea-level equivalents at the same latitude. These figures represent physics-derived benchmarks for a well-installed system with no shading or snow losses.

Annual Benchmarks by System Size and Region

Estimated annual production (kWh) by system size and Colorado region. Based on pvlib modeling with Open-Meteo ERA5 climate data.

System Size	Denver Front Range	Grand Junction	Colorado Springs	Fort Collins	Mountain Resorts (Aspen/Vail)
4 kW	6,720	7,360	6,840	6,640	6,320
6 kW	10,080	11,040	10,260	9,960	9,480
8 kW	13,440	14,720	13,680	13,280	12,640
10 kW	16,800	18,400	17,100	16,600	15,800
12 kW	20,160	22,080	20,520	19,920	18,960

Specific yield (kWh/kW/year): Denver ~1,680 | Grand Junction ~1,840 | Colorado Springs ~1,710 | Fort Collins ~1,660 | Mountain Resorts ~1,580

Climate Zones and Performance Ratio Targets

Climate Zone	Representative City	Specific Yield (kWh/kW/yr)	Performance Ratio Target
Semi-arid High Plains	Denver	1,680	0.80-0.85
High Desert (western slope)	Grand Junction	1,840	0.79-0.84
Semi-arid (southern Front Range)	Colorado Springs	1,710	0.80-0.85
Semi-arid (northern Front Range)	Fort Collins	1,660	0.80-0.85
Subalpine	Aspen	1,580	0.79-0.84

Colorado's high-altitude, low-humidity atmosphere produces excellent performance ratios. The main PR losses come from occasional heavy soiling events and, for mountain systems, snow coverage in winter months. Denver's moderate summer temperatures (relative to desert states) allow panels to operate closer to rated efficiency during peak production months.

What Affects Colorado Solar Output

High altitude irradiance boost: Denver sits at 5,280 feet. The thinner, drier atmosphere filters less incoming solar radiation, boosting available irradiance approximately 6-8% compared to sea-level locations at the same latitude. Grand Junction at 4,600 feet in an arid basin captures even more, contributing to its 1,840 kWh/kW/year specific yield.
Snow coverage in winter: December through February bring meaningful snowfall along the Front Range and heavier accumulation in mountain areas. Snow resting on panels blocks production entirely until it slides off or melts. A 30-degree tilt helps self-clearing but does not eliminate the problem. Mountain resort systems can lose 10-15% of December-February potential output to snow coverage.
Hail belt risk: Colorado sits within the US hail belt. Large hail events can physically damage panels and microcracks from smaller impacts can degrade output over time. Choosing panels with IEC 61215 hail resistance ratings and verifying coverage under homeowner insurance before installation is practical due diligence.
Ground-reflected albedo from snow: Snow-covered surroundings reflect additional radiation onto panel surfaces, providing a modest albedo gain of 3-7% during winter months when snow is present but panels remain clear. This partially offsets low sun angles in December and January.
Afternoon thunderstorms (July-August): Colorado's monsoon-influenced afternoon storm pattern reduces July and August production relative to June, even though days are still long. Denver's July output at 1,090 kWh trails June at 1,120 kWh for this reason.

Frequently Asked Questions

What is a good annual output for a 6 kW system in Colorado?

A well-installed 6 kW system in Denver should produce 9,800-10,400 kWh per year. Grand Junction systems can reach 10,800-11,300 kWh annually. Mountain systems in Aspen or Vail typically produce 9,200-9,800 kWh due to snow losses and weather variability. If your system falls more than 10% below the expected range without a documented cause, a technical review is appropriate.

Does snow on panels significantly hurt Colorado solar production?

For Front Range systems, snow causes modest annual losses, typically 2-5% of annual production. Most snow slides off within one to two days on a 30-degree tilted array. The loss is concentrated in December and January, which are already the lowest-production months. Mountain systems face larger losses of 8-15% annually from snow. Manual clearing is cost-effective only for mountain systems with frequent persistent snowpack.

Does Colorado's altitude make solar panels more efficient?

Altitude increases the solar resource available to panels, not panel efficiency itself. Panels convert the same percentage of incoming light regardless of altitude. But because more solar radiation reaches the panels at altitude (less atmospheric absorption), total energy production per kilowatt of installed capacity is higher. The 6-8% irradiance gain at Denver's elevation is a meaningful contributor to the state's strong specific yield.

How do I get an independent benchmark for my Colorado system?

Enter your system's location, size, tilt, and azimuth at solarbenchmark.io. The tool runs pvlib physics modeling against Open-Meteo ERA5 historical weather data for your exact coordinates, producing a monthly production benchmark you can compare directly to your inverter or utility monitoring data. See the full methodology for data sources and assumptions.

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