Solar Sun Angle Calculator
The angle at which sunlight strikes a solar panel determines how much energy is captured. A panel tilted perpendicular to the sun's rays captures maximum energy. Since the sun's elevation varies with latitude, season, and time of day, the optimal fixed tilt for a stationary panel depends primarily on latitude. The standard rule is: annual optimum tilt equals the site latitude (in degrees). Seasonal adjustments improve yield further. This calculator uses latitude to determine the annual, summer, and winter optimal tilt angles, and also computes the noon solar elevation at the summer and winter solstices.
Solar tilt and sun angle formulas
Annual optimal tilt = latitude
Summer optimal tilt = latitude - 15 degrees
Winter optimal tilt = latitude + 15 degrees
Noon elevation (solstice) = 90 - latitude +/- 23.45 degrees
Solar declination at summer solstice is +23.45 degrees (northern hemisphere) and -23.45 degrees at winter solstice. Noon solar elevation = 90 - (latitude - declination). Panels should tilt toward the equator (south in northern hemisphere).
Tilt reference by US city latitude
Miami (25.8 N): annual tilt 25.8 degrees. Los Angeles (34 N): 34 degrees. Denver (39.7 N): 39.7 degrees. Chicago (41.8 N): 41.8 degrees. Seattle (47.6 N): 47.6 degrees. Anchorage (61.2 N): 61.2 degrees. These are the annual optimum fixed tilt angles for maximum energy yield.
Solar panel angle: frequently asked questions
What is the optimal tilt angle for a fixed solar panel?
For a fixed (non-tracking) solar panel in the northern hemisphere, the annual optimal tilt is approximately equal to the site latitude. This maximizes total annual energy capture. For summer optimization, subtract 15 degrees from latitude; for winter, add 15 degrees.
What is solar declination?
Solar declination is the angle between the Sun's rays and the Earth's equatorial plane. It varies from +23.45 degrees at the June solstice to -23.45 degrees at the December solstice. This seasonal variation is why the optimal tilt differs between summer and winter.
Should I adjust my panels seasonally?
Adjusting twice a year (once for summer, once for winter) can increase annual energy yield by 5 to 10% compared to a fixed optimal angle. More frequent adjustments give diminishing returns. A solar tracker (2-axis) can increase yield by 25 to 40%.
What direction should panels face in the northern hemisphere?
Fixed panels in the northern hemisphere should face true south (not magnetic south) to receive maximum direct sun during the day. In the southern hemisphere, panels should face true north.
What about latitude zero (equator)?
At the equator, the annual optimal tilt is approximately 0 degrees (flat). This is because the Sun passes nearly overhead throughout the year. Some slight tilt (5-10 degrees) is often used for rain runoff and self-cleaning.
Official sources
- NREL PVWatts - National Renewable Energy Laboratory: pvwatts.nrel.gov.
- DOE Office of Energy Efficiency - Solar Basics: energy.gov.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.