Tilt your solar panels to 45° facing south in IV20. That is the most efficient fixed angle for its latitude of 57.79°. The full breakdown, including seasonal and monthly adjustments, is below.
The IV20 postcode district is centered 14.2 miles from Nairn, at latitude 57.79°. Every angle here is calculated from that center rather than from the nearest large town. Latitude moves the answer very little in Britain: across the whole country, from the Isles of Scilly to Shetland, the best fixed tilt only runs from 42.1° to 45.9°.
Today, the most efficient tilt for photovoltaic panels in IV20 is 53.2°, facing south. At solar noon the sun sits 36.8° 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. IV20 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 45°.
If you're planning to change the angle of your photovoltaic panels twice per year, the most efficient angle is 32.7° facing south in summer months and 69.8° facing south in winter months.
When changing the angle of your photovoltaic panels each season, the most efficient angle is 28.9° facing south in summer months and 75.4° facing south in winter months, and 54.3° facing south in autumn and spring months.
If you adjust your photovoltaic panels every month, the table below gives the most efficient angle for IV20 throughout the year. The shallowest angle is 34.4° in June, and the steepest is 81.2° in December.
| Month | Optimal tilt | Sun angle at noon |
|---|---|---|
| January | 77.9° | 12.1° |
| February | 69.0° | 21.0° |
| March | 58.2° | 31.8° |
| April | 46.2° | 43.8° |
| May | 37.7° | 52.3° |
| June | 34.4° | 55.6° |
| July | 37.4° | 52.6° |
| August | 46.0° | 44.0° |
| September | 58.0° | 32.0° |
| October | 69.6° | 20.4° |
| November | 78.2° | 11.8° |
| December | 81.2° | 8.8° |
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.
It comes out of your latitude. IV20 sits at 57.79°, which puts the best fixed angle at 45°. 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:
Postcode district data contains OS data © Crown copyright and database right, and Royal Mail data © Royal Mail copyright and database right, used under the Open Government Licence v3.