I’m exploring why solar panels should point different ways in different places.
Think of a panel as a sunlight catcher: where you are and how high the Sun gets help determine which way to aim it.
A panel catches light more directly when it faces the Sun. Because Earth is round and tilted, the Sun’s path changes with location and season. This gives a simple starting direction and tilt, then explains the geometry behind them.
Try this: Compare San Juan with Sydney and watch the compass flip. Then switch between summer and winter to see how the suggested tilt changes.
This is a starting estimate. Shade, roof shape, weather, and when you need power can change the best setup. Roof data, when available, is shown separately.
A latitude-based starting point for fixed panels. Roof slope, shade, and local weather affect the best setup.
Click a point to update the estimate.
San Juan is 18.5° north of the equator. Facing south points the panels toward the equator, a useful starting direction for annual sunlight.
Here in the tropics, the noon Sun crosses to both sides during the year, so this direction is a starting point rather than an all-season optimum.
Around the equinoxes, the Sun at solar noon is about 71.5° above the horizon here. A panel tilted 18.5° from horizontal faces that light directly. More face-on sunlight means more energy reaches each square meter.
The gold ray in the diagram illustrates face-on light; it is not a live Sun tracker.
Earth’s tilted axis shifts the Sun’s path through the year. A flatter panel can favor the higher summer Sun; a steeper panel can favor the lower winter Sun. Year-round tilt balances the seasons without adjusting the mount.
Optional Google Solar estimates for the nearest covered building.
For fixed panels, facing toward the equator and tilting approximately to your latitude is a useful starting point. Directions refer to true north or south, rather than magnetic north. At the equator, this simple model gives a horizontal panel with no preferred compass direction.
Summer and winter apply a rough −15° or +15° tilt adjustment, limited to 0–90°. The month labels switch with the hemisphere. These are rules of thumb, not a simulation of your roof or a monthly energy forecast.
Roof coverage varies by location. Google may return a nearby building; check the matched coordinates. The optional full-sun metric uses annual roof sunshine quantiles in kWh/kW/year, divided by 365.