Sun Hours
Hours during the day when the sun is above the horizon (horizontally midnight to midnight) throughout the year (vertically January to December) at locations of varying altitude from 90°N (North Pole) to 90°S (South Pole).
Note that for northern and southern places the sun never sets or raises in parts of the year, whereas close to the equator the hours of sunlight hardly change through the year.
White vertical lines mark 6:00/12:00/18:00 of the local time (without daylight savings). Weak horizontal lines show the month boundaries.
The images below show the same for fixed locations:
- NorthPole 90.0°N: the horizontal structure represents the fact that during certain parts of the year the sun is above the horizon for the whole day (summer months) and for the winter months is not visible at all
- Longyearbyen (Spitzbergen) 78.217°N: still very far in the north, i.e., above the Polar Circle, winters are dark throughout out the day and the sun never sets in summer - but there is now variation in the day length during the transition
- Switzerland 47.326°N: now below the Polar Circle, so the sun is visible some part of the time every day. The ‘jumps’ in the hours of sunlight come from the switching to and from daylight saving times
- Rome 12.5°N: length of the days are much more similar, as Rome is closer to the equator. Again the jumps in the hours of sunlight stem from daylight savings time
- Singapore 1.290°N: being close to the equator means the hours of sunlight are nearly equal through the year (therefore also no daylight savings time)
- Cape Town 33.917°S: now on the southern hemisphere, so winter and summer months switch place
- Antarctica Neumayer Station 70.67°S: this is south of the southern Polar Circle, so again the sun stays down part of the year - but here that is in the months around July
- South Pole 90.0°S: similar to the North Pole, with summer and winter switched
The underlying calculations of the sun position have been done using the nice and concise code given by
Python Sun Position for Solar Energy and Research | by John Clark Craig | Level Up Coding
(after conversion to Kotlin).