klepZ ArrayCare

Solar by state / Alaska

Solar potential
in Alaska.

Daily irradiance2.5kWh/m² average, 2.3–2.6 across the state
Per kW installed680kWh a year, south-facing at 0.80 PR
Strongest monthJune5.0 kWh/m² a day
National rank51 / 51by sampled irradiance

Alaska averages 2.5 kWh per square metre a day across the 8 grid cells sampled inside it — the least sunny state in the country by that measure. June is the strongest month at 5.0, December the weakest at 0.2.

What that means for an array

On the same assumptions the ArrayCare check uses — a south-facing array and a 0.80 performance ratio — that works out to roughly 680 kWh a year for every kW installed, or 4,760 kWh for a 7 kW system. Irradiance is what arrives; production is what a specific array, at a specific tilt, with specific shading and losses, converts. Those are different numbers and a real quote will use the second.

Where in the state

The spread inside Alaska runs from 2.3 kWh/m²/day around Chugach Census Area to 2.6 around Lake and Peninsula Borough — 11% between the dimmest and sunniest sampled cells, or about 67 kWh a year per kW installed. That is a real difference, though a roof's orientation and shading will usually move the number further than its county does.

How precise this is

These figures come from NASA POWER's solar climatology, a grid of roughly 55 km cells. Two points 40 km apart return the same numbers, which is why this page covers a state and prints the range across 8 sampled cells rather than claiming a figure for a town or a ZIP code. Local terrain, coastal fog and elevation all move the real number at a given address, and none of them are visible at this scale.

Through the year

June runs 23.7× stronger than December. That is an extreme seasonal swing. Winter output is close to negligible, and an annual average badly misdescribes a year shaped like that.

MonthkWh/m² a daykWh per kW installed
January 0.3 8
February 1.0 21
March 2.4 56
April 4.0 90
May 4.9 115
June 5.0 112
July 4.4 103
August 3.5 80
September 2.3 52
October 1.2 27
November 0.5 10
December 0.2 5

Monthly means across the 8 sampled cells. The per-kW column applies a south-facing orientation and a 0.80 performance ratio to the irradiance beside it — the same arithmetic the array check uses.

The cells behind these numbers

Each row is one NASA POWER grid cell, named for the county its sample point falls in. Two counties in the same cell would return the same numbers, so only one of each appears.

Sample pointkWh/m² a daykWh a year per kW
Lake and Peninsula Borough2.6707
Matanuska-Susitna Borough2.6706
Fairbanks North Star Borough2.6703
Haines Borough2.5694
Wrangell City and Borough2.4668
North Slope Borough2.4667
Aleutians West Census Area2.4656
Chugach Census Area2.3640

Against the rest of the country

For scale, Arizona leads the country at 5.8 kWh/m²/day and Alaska trails at 2.5. The national spread is narrower than most people expect — the sunniest state is not ten times the dimmest, it is about 2.3×.

Sunlight is only one input into whether solar pays somewhere. Electricity prices, net-metering rules, incentives, roof condition and shading routinely matter more than the difference between two neighbouring states, and none of them are on this page. ArrayCare is independent, sells nothing, and is not a quote.

States with similar sun

All 51 states ranked →