Tilt your solar panels to 40.6° facing south in Headquarters. That is the most efficient fixed angle for its latitude of 46.63°. The full breakdown, including seasonal and monthly adjustments, is below.
Today, the most efficient tilt for photovoltaic panels in Headquarters is 42.4°, facing south. At solar noon the sun sits 47.6° above the horizon. Setting your panels to this angle keeps them as close to perpendicular to the sun as possible, which is where they generate the most electricity.
Your photovoltaic panels need to be angled facing south. Headquarters is in the northern hemisphere, so panels catch the most sun facing south.
If you're mounting the photovoltaic panels at a stationary angle, such as on your roof, the most efficient angle is 40.6°.
If you're planning to change the angle of your photovoltaic panels twice per year, the most efficient angle is 22.4° facing south in summer months and 60° facing south in winter months.
When changing the angle of your photovoltaic panels each season, the most efficient angle is 18.6° facing south in summer months and 65.5° facing south in winter months, and 43.4° facing south in autumn and spring months.
A 400W panel at its best fixed angle in Headquarters makes about 467 kWh a year, worth $55.21 at 11.82 cents per kWh, the 2025 residential average for Idaho. Per kilowatt of panels that is 1,168 kWh, or $138.03, a year.
A home in Idaho uses about 11,068 kWh of electricity a year, so covering all of it from the roof in Headquarters takes roughly 24 panels of that size. Fewer panels cover proportionally less of it.
If you adjust your photovoltaic panels every month, the table below gives the most efficient angle for Headquarters throughout the year. The shallowest angle is 23.2° in June, and the steepest is 70.0° in December.
| Month | Optimal tilt | Sun angle at noon |
|---|---|---|
| January | 66.7° | 23.3° |
| February | 57.8° | 32.2° |
| March | 47.0° | 43.0° |
| April | 35.0° | 55.0° |
| May | 26.5° | 63.5° |
| June | 23.2° | 66.8° |
| July | 26.2° | 63.8° |
| August | 34.8° | 55.2° |
| September | 46.8° | 43.2° |
| October | 58.4° | 31.6° |
| November | 67.0° | 23.0° |
| December | 70.0° | 20.0° |
The sun angle at noon is how high the sun sits above the horizon at midday. Facing your panels south at the tilt shown for each month keeps them as close to perpendicular to the sun as possible, which is where they generate the most electricity.
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It comes out of your latitude. Headquarters sits at 46.63°, which puts the best fixed angle at 40.6°. Near the equator the midday sun is almost overhead, so panels lie close to flat, around 3°. The further from the equator you are, the lower the sun sits, and the steeper your panels have to stand to face it squarely.
The climb is not one for one. At 30° of latitude the best fixed tilt is about 31°, but at 60° of latitude it is about 46°, not 60°. The optimum flattens off toward the poles because the winter sun is low and much of the light arriving is diffuse rather than direct. Every angle on this page comes from a curve fitted to measured optimal-slope data for 52 cities, so it follows that flattening instead of assuming tilt equals latitude. See how the two compare.
The angle is settled. Here is what is worth checking on the panels themselves:
Generation modeled with PVGIS at this location's own coordinates, © European Union, 2001-2026. Electricity prices from the US Energy Information Administration.