Arizona Solar Panel Performance Benchmarks
Last updated: 2026-04-06 · Solar Benchmark
Arizona Solar Panel Performance Benchmarks
A 6kW solar system in Arizona produces between 10,500 and 11,400 kWh per year, making it one of the highest-producing solar states in the US. Phoenix averages about 11,100 kWh/year for a 6kW system. Tucson runs similarly. Flagstaff, at 7,000 feet elevation, is cooler and sunnier in summer but gets more winter clouds, averaging around 10,500 kWh. Arizona systems produce 35–45% more than equivalent systems in the Mid-Atlantic, entirely because of irradiance.
Monthly Production Benchmarks: Arizona 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, Phoenix as the statewide reference location.
| Month | Expected Production (kWh) | Notes |
|---|---|---|
| January | 626 | Cool, sunny; low sun angle |
| February | 790 | Strong early-year output |
| March | 988 | Excellent spring production |
| April | 1,122 | Peak spring; mild temperatures |
| May | 1,200 | Best month; low humidity, high sun |
| June | 1,168 | Near-peak; very hot afternoons reduce late-day output |
| July | 1,050 | Monsoon season begins; afternoon storms |
| August | 1,030 | Monsoon continues; heat remains high |
| September | 1,026 | Monsoon ends; recovery |
| October | 920 | Excellent fall output |
| November | 724 | Gradual seasonal decline |
| December | 548 | Lowest month; still solid |
| Annual Total | ~11,192 | Phoenix-area 6kW reference |
(Source: pvlib physics modeling, Open-Meteo ERA5 weather data)
Annual Benchmarks by System Size and Arizona Region
| System Size | Phoenix Metro | Tucson | Yuma | Flagstaff | Prescott |
|---|---|---|---|---|---|
| 4 kW | 7,460 | 7,360 | 7,680 | 7,000 | 7,240 |
| 6 kW | 11,190 | 11,040 | 11,520 | 10,500 | 10,860 |
| 8 kW | 14,920 | 14,720 | 15,360 | 14,000 | 14,480 |
| 10 kW | 18,650 | 18,400 | 19,200 | 17,500 | 18,100 |
| 12 kW | 22,380 | 22,080 | 23,040 | 21,000 | 21,720 |
Phoenix specific yield: ~1,865 kWh/kW/year. Tucson: ~1,840. Yuma: ~1,920. Flagstaff: ~1,750. Prescott: ~1,810.
(Source: pvlib physics modeling, Open-Meteo ERA5 weather data, 2015–2024 averages)
Arizona Climate Zones and Performance Ratio Targets
Arizona's performance ratios run lower than cooler-climate states because heat suppresses panel efficiency. A PR of 0.78–0.84 is normal for Phoenix in summer. Nationally comparable PR thresholds still apply for flagging problems.
| Climate Zone | Representative City | Annual Specific Yield | Expected PR Range |
|---|---|---|---|
| Sonoran Desert Low (Phoenix, Yuma) | Phoenix | 1,820–1,950 kWh/kW | 0.76–0.86 |
| Sonoran Desert Mid (Tucson) | Tucson | 1,800–1,900 kWh/kW | 0.76–0.86 |
| High Desert (Flagstaff, Prescott) | Flagstaff | 1,720–1,820 kWh/kW | 0.78–0.88 |
Learn more about how these benchmarks are calculated at /resources/methodology.
What Affects Arizona Solar Output
- Heat losses: Arizona summer temperatures regularly exceed 110°F (43°C). At 80°C panel temperature, common during peak summer afternoons in Phoenix, a typical PERC module loses about 22% of rated output at that instant. Annual heat losses across Arizona systems range from 7–12% of potential production.
- Monsoon season (July-September): Arizona's North American Monsoon brings afternoon and evening thunderstorms from early July through mid-September. These dramatically reduce afternoon production. July and August in Phoenix produce 10–15% less than May despite similar daylight, primarily because of monsoon clouds and the combined heat effect. Systems that appear to underperform in July aren't necessarily broken.
- Dust soiling: The Sonoran Desert's fine dust accumulates rapidly on panels during dry season (October through June). Without cleaning, soiling losses of 5–10% are common by late spring. One cleaning before monsoon season and one cleaning before summer are the typical Arizona maintenance schedule.
- UV degradation: Intense UV in Arizona accelerates panel degradation slightly above the national average. Arizona PERC systems typically show 0.55–0.65%/year degradation vs. 0.50%/year in cooler states.
Frequently Asked Questions
Q: What should a 6kW solar system produce per month in Phoenix?
A: The Phoenix benchmark averages about 933 kWh/month. May is the peak month at roughly 1,200 kWh. December is the lowest at around 548 kWh. July and August drop below June due to the monsoon season; this is expected, not a system problem. A Phoenix system producing below 850 kWh in May warrants a closer look.
Q: Why does my Arizona system produce less in July than in May even though July has more daylight?
A: Two factors: monsoon clouds reduce daily irradiance by 15–25%, and extreme heat reduces panel efficiency during afternoon peak hours. May has clear skies, mild-to-warm temperatures, and high sun angles. The combination makes May the benchmark month for Arizona systems, not July.
Q: Does soiling really matter in Arizona?
A: Yes, more than in most states. Phoenix averages fewer than 8 inches of rain per year, which means panels go months without natural cleaning. A system that misses its annual cleaning in a dry year can lose 8–10% of output to accumulated dust. For a 10kW system producing 18,650 kWh/year, that's 1,490–1,865 kWh lost, roughly two months of winter production.
Q: How do I get an independent benchmark for my Arizona solar system?
A: A valid benchmark for Arizona requires weather data that captures monsoon variability, not just annual averages. ERA5 hourly data tracks actual cloud cover and temperature year by year, giving a month-by-month expected production figure that accounts for whether a given monsoon was strong or weak. Learn more at /resources/methodology.
Data: pvlib physics modeling + Open-Meteo ERA5 weather data | Last updated: 2026-04-06 | Solar Benchmark