klepZ ArrayCare

Solar by state / Michigan

Solar potential
in Michigan.

Daily irradiance3.6kWh/m² average, 3.4–3.8 across the state
Per kW installed998kWh a year, south-facing at 0.80 PR
Strongest monthJuly6.2 kWh/m² a day
National rank49 / 51by sampled irradiance

Michigan averages 3.6 kWh per square metre a day across the 8 grid cells sampled inside it — 49th of 51 states by that measure. July is the strongest month at 6.2, December the weakest at 1.0.

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 998 kWh a year for every kW installed, or 6,986 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 Michigan runs from 3.4 kWh/m²/day around Keweenaw County to 3.8 around Berrien County — 11% between the dimmest and sunniest sampled cells, or about 103 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

July runs 6× 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 1.3 30
February 2.1 46
March 3.5 80
April 4.6 104
May 5.5 128
June 6.1 138
July 6.2 144
August 5.3 122
September 4.0 91
October 2.5 58
November 1.5 34
December 1.0 24

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
Berrien County3.81,046
Eaton County3.81,040
Bay County3.71,016
Ottawa County3.71,014
Kalkaska County3.61,000
Cheboygan County3.6976
Chippewa County3.4946
Keweenaw County3.4943

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 →