Solar by state / Texas
Solar potential
in Texas.
Texas averages 5.0 kWh per square metre a day across the 8 grid cells sampled inside it — 7th of 51 states by that measure. June is the strongest month at 7.0, December the weakest at 2.8.
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 1,366 kWh a year for every kW installed, or 9,562 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 Texas runs from 4.7 kWh/m²/day around Falls County to 5.3 around Dallam County — 12% between the dimmest and sunniest sampled cells, or about 157 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.
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 2.5× stronger than December. A winter month delivers under half of a summer month, which is the normal shape for most of the country.
| Month | kWh/m² a day | kWh per kW installed | |
|---|---|---|---|
| January | 3.1 | 72 | |
| February | 3.7 | 78 | |
| March | 4.8 | 111 | |
| April | 5.8 | 130 | |
| May | 6.3 | 147 | |
| June | 7.0 | 158 | |
| July | 6.9 | 161 | |
| August | 6.4 | 149 | |
| September | 5.3 | 120 | |
| October | 4.4 | 102 | |
| November | 3.3 | 75 | |
| December | 2.8 | 64 |
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 point | kWh/m² a day | kWh a year per kW |
|---|---|---|
| Dallam County | 5.3 | 1,457 |
| Floyd County | 5.3 | 1,454 |
| Throckmorton County | 5.1 | 1,393 |
| Blanco County | 4.9 | 1,352 |
| Cameron County | 4.8 | 1,332 |
| Bosque County | 4.8 | 1,322 |
| DeWitt County | 4.8 | 1,317 |
| Falls County | 4.7 | 1,300 |
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.