The Dirtiest Cities in America for Solar Panels (2026)
Dust, pollen, and long dry seasons quietly tax solar output — NREL research documents 5–25% annual losses in high-soiling regions. We ranked the metros in our directory on a national Grime Index built from dust-season length, regional soiling composition, and cleaning cadence. The worst offender, Fresno, costs a typical 7 kW home an estimated $520/year in lost production when panels go uncleaned.
- ~15% lost/yr uncleaned~$520/yr lost on a 7 kW systemDust season: Jun–OctPros recommend 3–4× / year
What’s on the glass here: ~55% dust · 30% pollen · 15% bird droppings.
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- ~15% lost/yr uncleaned~$259/yr lost on a 7 kW systemDust season: May–SepPros recommend 3–4× / year
What’s on the glass here: ~65% dust · 20% pollen · 15% bird droppings.
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- ~15% lost/yr uncleaned~$248/yr lost on a 7 kW systemDust season: Jun–SepPros recommend 2–4× / year
What’s on the glass here: ~65% dust · 20% pollen · 15% bird droppings.
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- ~12% lost/yr uncleaned~$416/yr lost on a 7 kW systemDust season: Jul–OctPros recommend 2–3× / year
What’s on the glass here: ~55% dust · 30% pollen · 15% bird droppings.
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- ~12% lost/yr uncleaned~$198/yr lost on a 7 kW systemDust season: May–SepPros recommend 2–4× / year
What’s on the glass here: ~65% dust · 20% pollen · 15% bird droppings.
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- ~12% lost/yr uncleaned~$200/yr lost on a 7 kW systemDust season: Mar–Jun (peak windy dust season), with a secondary bump in Jul–Sep monsoon dust ahead of storms; juniper/cottonwood/elm pollen adds a sticky film in Feb–AprPros recommend 2–3× / year
What’s on the glass here: ~65% dust · 20% pollen · 15% bird droppings.
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- ~12% lost/yr uncleaned~$215/yr lost on a 7 kW systemDust season: Apr–Sep (spring wind-driven playa dust in Apr–May, then dry summer dust plus Jul–Sep wildfire ash; winter inversion soot Dec–Feb is a secondary peak; tree/grass pollen in Apr–May is present but dust dominates)Pros recommend 2–3× / year
What’s on the glass here: ~65% dust · 20% pollen · 15% bird droppings.
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- ~12% lost/yr uncleaned~$183/yr lost on a 7 kW systemDust season: Jun–SepPros recommend 2× / year
What’s on the glass here: ~55% dust · 30% pollen · 15% bird droppings.
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- ~10% lost/yr uncleaned~$347/yr lost on a 7 kW systemDust season: Aug–OctPros recommend 2× / year
What’s on the glass here: ~55% dust · 30% pollen · 15% bird droppings.
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- ~10% lost/yr uncleaned~$157/yr lost on a 7 kW systemDust season: Apr–May (tree/grass pollen dominates), with a secondary Jul–Sep haze/particulate peakPros recommend 1–2× / year
What’s on the glass here: ~45% dust · 35% pollen · 20% bird droppings.
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- #11Boise, Idaho~10% lost/yr uncleaned~$157/yr lost on a 7 kW systemDust season: Jun–Sep (high-desert dust plus Aug–Sep wildfire ash); secondary spring pollen/juniper bloom Apr–MayPros recommend 2–3× / year
What’s on the glass here: ~30% dust · 50% pollen · 20% bird droppings.
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- ~10% lost/yr uncleaned~$157/yr lost on a 7 kW systemDust season: Mar–Jun, with pollen (cedar/oak/grass) dominating Mar–May and wind-driven red-clay/agricultural dust peaking Apr–Jun; secondary dry-dust window Jul–SepPros recommend 2× / year
What’s on the glass here: ~45% dust · 35% pollen · 20% bird droppings.
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- ~10% lost/yr uncleaned~$157/yr lost on a 7 kW systemDust season: Jun–Sep (wheat harvest and late-summer dry spell dust); secondary spring pollen peak Apr–May (cedar, oak, grass)Pros recommend 2× / year
What’s on the glass here: ~45% dust · 35% pollen · 20% bird droppings.
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- ~10% lost/yr uncleaned~$151/yr lost on a 7 kW systemDust season: Jul–Sep (peak: windblown agricultural/prairie dust plus wildfire smoke and ash fallout); secondary Mar–May windy dust season, with light tree/grass pollen in May–Jun that is not the dominant driverPros recommend 2× / year
What’s on the glass here: ~30% dust · 50% pollen · 20% bird droppings.
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- ~10% lost/yr uncleaned~$152/yr lost on a 7 kW systemDust season: Jul–SepPros recommend 2× / year
What’s on the glass here: ~55% dust · 30% pollen · 15% bird droppings.
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The rest of the ranking
| # | METRO | LOSS/YR | ≈ COST (7 kW) | DUST SEASON |
|---|---|---|---|---|
| #16 | Bend, Oregon | ~8% | $93 | Jun–Sep |
| #17 | Denver, Colorado | ~8% | $134 | Mar–Jun (peak windblown plains dust plus tree/grass pollen), with a secondary Jul–Sep wildfire-smoke and ash period |
| #18 | Cheyenne, Wyoming | ~8% | $125 | Mar–Jun (peak windblown prairie dust; secondary Jul–Aug dry spell; tree/grass pollen in May–Jun is a minor contributor) |
| #19 | Chicago, Illinois | ~8% | $125 | Apr–Jun (tree and grass pollen dominant), with a secondary Jul–Aug haze/urban-particulate buildup during dry spells |
| #20 | St. Petersburg, Florida | ~8% | $122 | Mar–Jun |
| #21 | Jacksonville, Oregon | ~8% | $93 | Jul–Sep (dry-season road/ag dust plus wildfire ash); secondary Apr–May conifer/oak/grass pollen film |
| #22 | Tampa, Florida | ~8% | $122 | Mar–Jun (pollen) |
| #23 | Louisville, Kentucky | ~8% | $125 | Mar–May (tree/grass pollen dominates; yellow-green film is the main soiling driver), with a secondary Jul–Sep haze/particulate period |
| #24 | Detroit, Michigan | ~8% | $125 | Apr–Jun (tree/grass pollen dominates), with a secondary Jul–Sep industrial-particulate and dry-spell haze period |
| #25 | Gainesville, Florida | ~8% | $122 | Feb–Apr |
| #26 | Honolulu, Hawaii | ~6.5% | $291 | May–Sep (dry-season salt spray + trade-borne dust); vog haze episodes during Kona-wind spells Oct–Apr |
| #27 | Miami, Florida | ~6.5% | $99 | Mar–Jun (pollen) |
| #28 | Davie, Florida | ~6.5% | $99 | Feb–May |
| #29 | Omaha, Nebraska | ~6.5% | $102 | Apr–May (tree/grass pollen plus spring field tillage dust) and Sep–Oct (corn/soybean harvest dust); pollen dominates the spring peak |
| #30 | Birmingham, Alabama | ~6.5% | $102 | Mar–May (tree/pine pollen dominates; secondary organic debris and soot Sep–Nov) |
| #31 | Atlanta, Georgia | ~6.5% | $102 | Feb–May (pine/oak pollen dominates, peaking late Mar–Apr); secondary organic debris and bird droppings from dense tree canopy in Jun–Aug |
| #32 | Eugene, Oregon | ~6.5% | $76 | May–Sep |
| #33 | Des Moines, Iowa | ~6.5% | $102 | Apr–May (planting dust + heavy tree/grass pollen) and Aug–Oct (harvest dust); fall harvest is usually the worst |
| #34 | Kansas City, Missouri | ~6.5% | $102 | Mar–May (tree/grass pollen dominates), with a secondary agricultural dust and pollen peak Aug–Oct during harvest and ragweed season |
| #35 | Jacksonville, Florida | ~6.5% | $99 | Feb–May |
| #36 | Sioux Falls, South Dakota | ~5.5% | $86 | Apr–May (planting dust + tree/grass pollen) and Aug–Oct (harvest-season field dust); fall tillage dust is the dominant driver |
| #37 | Salem, Oregon | ~5.5% | $64 | May–Sep |
| #38 | Orlando, Florida | ~5.5% | $84 | Feb–May |
| #39 | New York, New York | ~5.5% | $86 | Apr–Jun (tree/grass pollen dominates, peaking late Apr–May), with a secondary urban-soot and road-grime buildup Dec–Feb |
| #40 | Philadelphia, Pennsylvania | ~5.5% | $86 | Apr–May (tree/grass pollen dominates), with a secondary Jun–Aug haze/particulate period |
| #41 | Little Rock, Arkansas | ~5.5% | $86 | Mar–May (tree/pine pollen dominates; secondary light film Jul–Sep from summer haze and dry spells) |
| #42 | Hillsboro, Oregon | ~5.5% | $64 | Jun–Sep |
| #43 | Nashville, Tennessee | ~5.5% | $86 | Mar–May (tree/grass pollen dominates; secondary light soiling Jul–Sep during dry spells) |
| #44 | Key West, Florida | ~5.5% | $84 | Feb–Apr (dry-season salt-spray film builds with little rinsing) and Jun–Aug (Saharan Air Layer dust plumes); pollen is a minor, non-dominant factor |
| #45 | New Orleans, Louisiana | ~5.5% | $86 | Mar–May, with tree pollen (live oak catkins, pine) the dominant soiling agent; secondary organic/biofilm buildup Jun–Sep plus occasional Saharan dust plumes in late June–July |
| #46 | Jackson, Mississippi | ~5.5% | $86 | Feb–Apr (tree/pine pollen dominates; secondary organic debris late summer–fall) |
| #47 | Oviedo, Florida | ~5.5% | $84 | Feb–Apr (oak/pine pollen dominates), with secondary organic soiling Jun–Sep from summer storms, mold/algae film and lovebug residue in May and Sep |
| #48 | Miami Beach, Florida | ~5.5% | $84 | Mar–May (oak/pine pollen dominates, plus dry-season dust) with a secondary Jun–Jul Saharan dust (SAL) plume peak; heavy May–Oct rains largely self-clean the array |
| #49 | Baltimore, Maryland | ~5.5% | $86 | Mar–May (tree pollen dominates: oak, maple, pine), with a secondary Aug–Oct bump from humid-season haze, port/I-95 particulates and falling leaf debris |
| #50 | Charleston, South Carolina | ~5.5% | $86 | Feb–Apr (pine/oak pollen dominates); secondary salt-spray and organic debris buildup year-round near the coast |
| #51 | Boca Raton, Florida | ~5.5% | $84 | Feb–May (dry-season dust plus heavy oak/pine pollen dominates), with a secondary Jun–Jul Saharan dust (SAL) plume peak |
| #52 | Gresham, Oregon | ~5.5% | $64 | Jun–Sep |
| #53 | DeBary, Florida | ~5.5% | $84 | Feb–May (oak/pine pollen dominates; light dry-season dust). Summer Jun–Sep rains largely self-clean, but humidity drives algae/lichen streaking at panel lower edges year-round. |
| #54 | West Little River, Florida | ~5.5% | $84 | Feb–Apr (oak/pine pollen, dominant) with a secondary Jun–Aug Saharan dust (SAL) peak |
| #55 | Coral Terrace, Florida | ~5.5% | $84 | Feb–Apr dominated by oak/pine pollen and dry-season dust; secondary Jun–Aug Saharan dust (SAL) plumes |
| #56 | Fargo, North Dakota | ~5.5% | $86 | Apr–May and Sep–Oct (spring tillage/planting dust plus tree pollen in May; fall harvest dust from surrounding Red River Valley cropland) |
| #57 | Hood River, Oregon | ~5.5% | $64 | Jun–Sep (dry-season dust off the Gorge plus wildfire smoke/ash in Aug–Sep); a secondary Apr–May orchard and conifer pollen wave is often the more visible film on panels |
| #58 | Tigard, Oregon | ~5.5% | $64 | May–Sep — spring conifer and Willamette Valley grass-seed pollen (May–Jun) is the dominant soiling driver, followed by the rain-free Jul–Sep dry season with road dust and periodic wildfire ash; winter rain largely self-cleans, though damp shade promotes moss/algae at low tilt angles |
| #59 | DeLand, Florida | ~5.5% | $84 | Feb–Apr (oak/pine pollen dominates); secondary organic soiling Jun–Sep from bird droppings, lovebug residue, and Saharan dust intrusions in late Jun–Jul |
| #60 | Deltona, Florida | ~5.5% | $84 | Feb–Apr (oak/pine pollen dominates); secondary Jun–Jul Saharan dust haze |
| #61 | Indianapolis, Indiana | ~5.5% | $86 | Apr–May (tree/grass pollen dominates) with a secondary Sep–Oct farm-harvest dust peak |
| #62 | Beaverton, Oregon | ~5.5% | $64 | Apr–Jun (Douglas-fir/cedar pollen dominates), with a secondary Jul–Sep dry-season dust and wildfire-ash window |
| #63 | Charlotte, North Carolina | ~5.5% | $86 | Mar–May (tree/pine pollen dominates; secondary leaf-litter and pollen-residue buildup Oct–Nov) |
| #64 | Coral Gables, Florida | ~5.5% | $84 | Feb–Apr (oak/pine pollen dominates), with a secondary Jun–Jul Saharan dust (SAL) plume period |
| #65 | Minneapolis, Minnesota | ~5.5% | $86 | Apr–May (tree/grass pollen dominates, with spring field tillage dust); secondary Sep–Oct from regional harvest dust |
| #66 | Virginia Beach, Virginia | ~5.5% | $86 | Mar–May (tree/grass pollen dominates; light salt-spray film year-round, secondary late-summer haze) |
| #67 | Columbus, Ohio | ~5.5% | $86 | Apr–May (tree/grass pollen dominates), with a secondary Sep–Oct farm harvest dust bump |
| #68 | Milwaukee, Wisconsin | ~5.5% | $86 | Apr–May (tree/grass pollen dominates), with a secondary Sep–Oct bump from harvest dust and leaf litter |
| #69 | Wilmington, Delaware | ~5.5% | $86 | Apr–May (tree/grass pollen dominates, esp. oak and pine), with a secondary Oct–Nov leaf-litter and organic debris period |
| #70 | Boston, Massachusetts | ~5.5% | $86 | Apr–May (tree/oak/pine pollen dominates), with a secondary Oct–Nov leaf-litter and organic-debris period |
| #71 | Charleston, West Virginia | ~5.5% | $86 | Mar–May (tree pollen dominant — oak, maple, pine); secondary Oct–Nov leaf/organic debris and winter wood-smoke soot in valley inversions |
| #72 | Lake Oswego, Oregon | ~5.5% | $64 | Apr–Jun (conifer/Douglas fir pollen dominates, yellow-green film), with a secondary Jul–Sep dry spell of dust and wildfire smoke ash; winter rains largely self-clean the array |
| #73 | Dover, Ohio | ~5.5% | $86 | Apr–Jun (tree pollen dominant: oak, maple, pine), with a secondary Aug–Oct farm harvest dust and leaf-litter period |
| #74 | Port Orange, Florida | ~5.5% | $84 | Feb–May (oak/pine pollen dominates, peaking Mar–Apr); secondary salt-haze and Saharan dust episodes Jun–Aug |
| #75 | Hartford, Connecticut | ~5.5% | $86 | Apr–Jun (tree/grass pollen dominates), with a secondary Oct–Nov leaf-litter and soot period |
| #76 | Portland, Oregon | ~5.5% | $64 | Jun–Sep (dry-season dust plus late-summer wildfire ash); Douglas fir/conifer pollen dominates Apr–May |
| #77 | Seattle, Washington | ~5.5% | $46 | Apr–May (heavy conifer/alder pollen dominates) and Jul–Sep dry season dust plus wildfire smoke ash |
| #78 | West Linn, Oregon | ~5.5% | $64 | Jul–Sep (summer dry spell dust + wildfire smoke/ash); heavy Douglas-fir/cedar pollen Apr–Jun often dominates the visible yellow film, plus moss/algae streaking on low-tilt arrays in the wet season |
| #79 | Oregon City, Oregon | ~5.5% | $64 | Apr–May pollen-dominated (Douglas-fir/conifer and grass pollen), with a secondary Jul–Sep dry-season dust and wildfire-ash peak; Nov–Mar rains largely self-clean panels |
| #80 | Manchester, New Hampshire | ~5.5% | $86 | Apr–Jun (tree/pine pollen dominates; secondary organic soiling from leaf litter and pine needles Sep–Nov) |
| #81 | Anchorage, Alaska | ~5.5% | $86 | Mar–May (spring 'breakup' road-sand and glacial silt dust), with birch/spruce pollen peaking late Apr–May; snow cover, not dust, dominates winter losses |
| #82 | Providence, Rhode Island | ~5.5% | $86 | Apr–Jun (tree and grass pollen dominates; secondary Sep–Nov leaf litter and organic debris) |
| #83 | Burlington, Vermont | ~5.5% | $86 | Apr–Jun (tree/grass pollen dominates, with a late-Mar–Apr bump from winter road-sand dust) |
| #84 | Portland, Maine | ~5.5% | $86 | Apr–Jun (tree/grass pollen dominates; light coastal salt film and winter snow-melt grit are secondary) |
| #85 | Astoria, Oregon | ~5.5% | $64 | Jul–Sep (dry-season accumulation); spring pollen Apr–Jun (alder, Douglas fir) is the more visible nuisance, plus year-round moss/algae/lichen at panel edges from persistent damp |
How this ranking works
Our Grime Index scores every metro in our directory (85 today) on three disclosed inputs: dust-season length (longer dry, dusty stretches mean faster buildup), regional soiling composition (desert dust clings harder than pollen and resists rain rinsing), and the cleaning cadence local pros actually recommend. Close calls are settled by researched severity — dust-storm frequency, particle-pollution levels, precipitation timing, wildfire smoke, and pollen intensity, with sources on file. Loss percentages map ranks conservatively onto NREL’s documented 5–25% soiling-loss envelope; dollar figures use state-typical production and electricity rates for a 7 kW home system. Estimates, not measurements: your roof, tilt, and weather vary.
Estimate YOUR losses — free calculatorFor journalists & researchers
The full dataset — every ranked metro with loss estimates, dust seasons, cleaning cadences, and soiling composition — is free to download and use with attribution. Citation-ready: “A typical 7 kW Fresno home loses an estimated $520/year to panel grime — #1 of 85 metros on the national Grime Index (CleanMySolarPanels, 2026).” Methodology: metros scored on dust-season length, regional soiling composition, and recommended cleaning cadence, with close calls settled by researched severity; loss percentages sit conservatively inside NREL’s documented 5–25% envelope. When citing, please link this page.
⬇ Download the dataset (CSV)FAQ
Doesn’t rain clean solar panels?
Only partially. Rain rinses loose pollen but leaves mineral dust films — and in the ranked cities above, dust season is precisely when rain is scarce. Bird droppings and baked-on grime need actual washing.
How often should panels be cleaned in a high-dust city?
In the top-ranked metros, local pros typically recommend 2–4 professional cleans per year, timed around the dust season. In milder regions, once or twice a year usually holds losses under 6%.
Is professional cleaning worth it?
In the dustiest top-ranked metros, cleaning often pays for itself within months of recovered production; in the milder cities lower on this list it’s more of an annual-maintenance case. Either way, pros carry the deionized-water gear and roof safety equipment that protect both the panels and the warranty. Compare free quotes from vetted local companies to see real prices.