Key takeaways
- Best year-round fixed tilt ≈ your latitude (40° latitude → 40° tilt).
- Summer tilt ≈ latitude − 15°, winter tilt ≈ latitude + 15° for adjustable mounts.
- Spring and fall sit close to your latitude; all angles clamp to 0–90°.
- Aim panels due south (azimuth) — tilt and aim are two separate settings.
How to set solar panel tilt
The tilt angle is how far your panels lean back from flat (0°) toward vertical (90°). The goal is to point the modules as squarely at the sun as possible across the year. Because the sun's height in the sky depends on your latitude, that one number drives the best fixed tilt: set the panels to roughly your latitude and they will collect the most annual energy.
These are field rules of thumb, not exact optics — but they land within a couple of percent of the modelled optimum for most temperate sites. Seasonal adjustment matters because the sun climbs high in summer (so panels lie flatter) and stays low in winter (so panels stand steeper to face it).
Worked example: latitude 40°
At 40° latitude, the year-round tilt is simply 40°. For an adjustable mount, drop to 40 − 15 = 25° in summer and raise to 40 + 15 = 55° in winter. Spring and fall sit right around 40°, so a fixed 40° rack is a fair compromise if you never touch it.
Optimal tilt by latitude
| Latitude | Year-round | Summer | Winter |
|---|---|---|---|
| 25° | 25° | 10° | 40° |
| 35° | 35° | 20° | 50° |
| 40° | 40° | 25° | 55° |
| 45° | 45° | 30° | 60° |
| 50° | 50° | 35° | 65° |
Tilt is only half the job
Getting the angle right matters most once the rest of your system is honest. Confirm how much energy the array actually makes at your site with the solar output calculator, then make sure the panel count matches your loads using the solar array sizing calculator. Tilt sets the vertical angle; azimuth (facing due south) sets the direction — get both right and a fixed rack will quietly out-earn a poorly aimed tracker.
Frequently asked questions
What angle should solar panels be?
For the best annual output, set a fixed tilt roughly equal to your latitude — about 40° at 40° latitude. Nudge flatter for summer-heavy use or steeper for winter.
Does the best tilt angle change by season?
Yes. The sun is higher in summer and lower in winter, so summer tilt ≈ latitude − 15° and winter tilt ≈ latitude + 15°, with spring and fall near your latitude.
Is it better to mount panels flat or tilted?
Tilted almost always wins outside the tropics. Flat mounts lose output and shed rain, snow, and dust poorly — even 10–15° helps panels self-clean.
How much output do you lose at the wrong tilt?
Within ~15° of optimal costs only a few percent a year. Being 30–40° off, or flat when you should be steep, can cost 10–20% or more.
What is the difference between tilt and azimuth?
Tilt is the up-and-down angle from horizontal; azimuth is the compass direction. Aim panels due south (180°) and set tilt by latitude.
Should I use fixed or adjustable tilt mounts?
Fixed near your latitude is simplest. Adjustable mounts gain ~5–10% a year by going flatter in summer and steeper in winter.
Tilt rules of thumb follow standard solar-resource and irradiance guidance — see NREL solar resource. Use a modelling tool like PVWatts for a site-exact figure; the angles here are quick field estimates.
Last reviewed June 2026