Solar Elevation & Day Length Calculator
Calculate the solar elevation angle at local noon and approximate daylight hours for any latitude and day of the year.
Results
What is it?
Solar declination is the angle between the sun's rays and Earth's equatorial plane, ranging from +23.45 degrees (summer solstice, Jun 21) to -23.45 degrees (winter solstice, Dec 21). This determines the sun's maximum elevation at solar noon and the number of daylight hours at any latitude.
How to use
Enter your latitude (positive = North) and the day of the year (Day 1 = January 1st). Use 172 for the summer solstice and 355 for the winter solstice. The calculator shows the solar elevation angle at local noon and approximate daylight hours.
Example scenario
London (51.5 N) on the summer solstice (Day 172): solar elevation approximately 61.5 degrees, daylight approximately 16.7 hours. On the winter solstice (Day 355): solar elevation approximately 15 degrees, daylight approximately 7.7 hours.
Pro tip
Solar panel efficiency depends heavily on elevation angle ? panels at 90 degrees to the sun capture maximum power. Seasonal tilt adjustment (same angle as your latitude plus or minus 15 degrees seasonally) can boost annual yield by 10-15% vs. fixed horizontal mounting.