Solar Panel Tilt Table
| Month (15th) | Tilt at 30°N | 40°N | 50°N | Rule |
|---|---|---|---|---|
| January | 51° | 61° | 71° | latitude + 21 - the steep winter sun-catch |
| February | 43° | 53° | 63° | steepening from the equinox |
| March | 32° | 42° | 52° | equinox: tilt = latitude |
| April | 21° | 31° | 41° | flattening toward summer |
| May | 11° | 21° | 31° | near-flat mornings pay |
| June | 7° | 17° | 27° | solstice: latitude - 23 |
| July | 8° | 18° | 28° | summer floor holds |
| August | 16° | 26° | 36° | climbing back |
| September | 27° | 37° | 47° | equinox: tilt = latitude again |
| October | 38° | 48° | 58° | winter posture returns |
| November | 48° | 58° | 68° | the steep months earn their keep |
| December | 53° | 63° | 73° | solstice: latitude + 23 |
A solar panel makes the most power when it faces the sun square-on, and the sun's noon height changes by 46 degrees between solstices - so the optimal tilt swings with it. The table gives the monthly tilt for three latitudes, from the near-flat June floor to the steep December catch.
Bottom line: the geometry is one line - tilt = latitude minus the sun's declination. At the equinoxes the declination is zero, so tilt equals latitude; June subtracts 23.4° (panels go nearly flat); December adds it (panels go steep). A hand-adjusted rack that moves twice a year - roughly the March and September equinox values - captures most of what monthly tracking would.
The honest part: the table optimizes noon perpendicularity, and real yields also care about mornings, afternoons, clouds and heat - which is why fixed-mount installers compromise at or slightly below latitude rather than tracking the table monthly. The steeper-than-latitude winter posture earns its keep twice over in cold climates: winter kilowatt-hours are the scarce ones, and a steep face sheds snow that would otherwise bury the array.
How to use
- Find your latitude's column; the row is the month's optimal tilt from horizontal.
- Fixed mount: build at your latitude (or a few degrees steeper north of the snow line) and stop optimizing - the table's spread is what the compromise buys away.
- Adjustable rack: move twice a year - steep (latitude +15) in early October, flat (latitude -15) in early April - and capture most of the monthly tracking gain.
Frequently asked questions
What angle should solar panels be set at?
For a fixed installation: your latitude, give or take - 30°N sets near 30°, 40°N near 40°, 50°N near 50°, measured from horizontal. That single compromise tracks the yearly average of the sun's noon height. If winters matter more than summers (they do in most heating-climate bills), add 10-15° of steepness; the table shows exactly what the monthly optimum would be.
Should I adjust my solar panels seasonally?
If the rack allows it, twice a year is the sweet spot: steeper around early October (latitude +15°), flatter around early April (latitude -15°). The gain over a fixed mount is real but modest - most studies put a well-chosen fixed angle within 5-10% of monthly tracking - so the adjustable hardware pays for itself mainly in snow country and high-latitude yards where winter steepness is worth more than the average.
What is the best solar panel angle in winter?
Steep: latitude plus roughly 23° at the December solstice - 63° at 40°N, 73° at 50°N. The winter sun crawls barely 25° above the horizon at those latitudes, and the low, southern arc slides across a steep face almost square-on. The practical bonus in snow country: a 60°-plus face sheds the snow that would keep a flat array dark for days after a storm.
Why does the optimal tilt equal latitude at the equinoxes?
Because the sun's noon altitude at the equinoxes is 90° minus your latitude - the geometry where a panel standing at exactly the latitude's tilt meets the sun perpendicular. The declination term that pushes the optimum up in winter and down in summer is zero at the equinoxes, which makes them the two calibration points of the whole table.
Does panel tilt matter as much as direction?
Direction (azimuth) is the bigger single decision: true south at northern-hemisphere latitudes is near-universally right, and being 45° off costs more than any tilt error. Within a south-facing mount, tilt errors cost a few percent per 10° away from optimal - real, but second-order. Get the azimuth right first, then let this table tune the tilt.