Sun Angle Daily: Guess Where the Sun Is

How to play

Every round names a place, a date and the time on the local clock, daylight saving included. Drag the arc to the sun's altitude, its height in degrees above a flat horizon (0° on the horizon, 90° straight overhead), and the dial to its direction, in degrees from true north going clockwise (east is 90°, south 180°, west 270°). On a keyboard, tab to either one and use the arrow keys. Lock it in and the game draws the sky at that moment: the horizon, the sun's path through the day, the sun itself and your guess as a dashed ring.

The three rounds get harder. The first is a city in the US or the UK, alternating day by day, with the sun well up. The second is a city elsewhere with the sun low, early or late in the day. The third is a twist, in turn: the far north in summer, a southern-hemisphere winter, a desert at noon, and a June noon in the tropics. Everyone gets the same puzzle on the same date, because the date itself picks it. A new one starts at midnight on your own clock, and the arrows under the game take you back to any earlier day. Your scores and streak are kept in this browser only; nothing is sent anywhere, and the share button hands your score to your phone's share sheet or copies it.

How the score works

The game measures how far your guess is from the sun on the sky: the angle between the two directions, as you would see it standing there. That is fairer than adding up the two errors, because near the top of the sky the direction hardly matters. Two guesses 85° up in opposite directions are only 10° apart on the sky, while two on the horizon 10° of direction apart are 10° apart too. The score is 100 × e^−(d/22)² for a miss of d degrees, rounded, and the day's score is the average of the three rounds. That curve is this game's own rule, chosen so that a near miss still scores well.

Points for a miss on the sky

Miss	5°	10°	15°	20°	30°	45°
Points	95	81	63	44	16	2

A streak counts the days you finish on the day itself. Playing an old day from the archive scores it but does not add to the streak.

Three rules that get you close

1. The noon height: 90 − latitude + declination

At solar noon, when the sun is highest, its altitude is 90° minus your latitude plus the sun's declination, the latitude where the sun is straight overhead that day. The declination swings between +23.44° at the June solstice and −23.44° at the December one, because that is the tilt of the Earth's axis to its orbit (NASA's Earth fact sheet gives the obliquity as 23.44°), and it is 0° at the equinoxes. In London (51.5°N) on June 21 that is 90 − 51.5 + 23.4 = 61.9°; on December 21, 90 − 51.5 − 23.4 = 15.1°. The solstice dates are the US Naval Observatory's for 2026. When the sun's declination is north of where you are, the noon sun is in the north instead and the rule becomes 90 + latitude − declination, with a southern latitude counted as negative: Sydney (33.9°S) on June 21 has 90 − 33.9 − 23.4 = 32.7°, in the north.

The noon sun on the 2026 solstices (this game's sums)

City	Latitude	June 21	December 21	Solar noon, June 21
Fairbanks	64.8°N	48.6° S	2.0° S	1:53 pm
London	51.5°N	61.9° S	15.1° S	1:02 pm
New York	40.7°N	72.7° S	25.9° S	12:58 pm
Madrid	40.4°N	73.0° S	26.2° S	2:17 pm
Phoenix	33.4°N	80.0° S	33.1° S	12:30 pm
Honolulu	21.3°N	87.9° N	45.3° S	12:33 pm
Sydney	33.9°S	32.7° N	79.6° N	11:57 am

The figures in the table and the game include refraction: the air bends sunlight and lifts the sun a little, by about half a degree on the horizon (0.48° by the correction NOAA uses) and by under a tenth of a degree once it is 10° up. That is why Fairbanks's low December sun reads 2.0° rather than the rule's 1.7°.

2. Solar noon is rarely 12:00

The sun turns 15° of its daily circle an hour (360° in 24 hours), so the time from solar noon tells you how far round it has gone. But solar noon falls when the sun crosses your meridian, not when the clock says 12. A time zone is wide, and a city at its western side sees the sun cross later; daylight saving adds an hour on top. Madrid keeps Central European time though it lies west of Greenwich, so on June 21 its solar noon is at 2:17 pm; London's, in British Summer Time, is at 1:02 pm. The Earth's tilted, slightly oval orbit then moves solar noon by up to a quarter of an hour through the year, which is called the equation of time: by this game's sums, in 2026 the sun runs 16.5 minutes ahead of an even clock on November 3 and 14.2 minutes behind on February 11. Each answer in the game says when solar noon fell that day.

3. The direction: south at noon, unless it is not

North of the Tropic of Cancer the noon sun is due south, and south of the Tropic of Capricorn it is due north. Between the tropics it can be either, depending on the date: in Honolulu on June 21 the noon sun is in the north, 87.9° up, and in December it is in the south. Away from noon, the sun is in the east in the morning and the west in the afternoon, and in summer it rises north of east and sets north of west, so on a long summer evening it is further round to the north than most people guess. Close to overhead, a few minutes move its direction a long way, which is why the score works on the sky and not on the dial.

In the far north the summer sun hardly sets. Fairbanks, at 64.8°N, sees it rise at 2:58 am and set at 12:48 am, just after midnight, on June 21, 2026 by this game's sums, so it is down for about 2 hours 10 minutes. Its lowest point, at solar midnight, is latitude + declination − 90 = 64.8 + 23.4 − 90 = −1.7°, just under the horizon. North of the Arctic Circle, at about 66°34′N, that sum comes out above zero around the June solstice and the sun does not set at all.

Why the sun's height matters for shade

A shadow's length is the height of whatever casts it divided by the tangent of the sun's altitude. A 6 ft (1.83 m) person with the sun 30° up casts a shadow 6 ÷ tan 30° = 10.4 ft (3.2 m) long; at 80°, Phoenix's June noon, it is 1.1 ft (0.32 m). The game shows that shadow after each round. The same sums decide where shade falls in a garden: a high sun is beaten from above and a low one from the side, which is the subject of how the sun moves across your garden and the best shade for a south-facing garden. The low winter sun slides under an awning that stops the summer sun, which is the case for retractable or fixed awnings and for a roof you can tilt (the louvered pergola guide). In the desert-noon rounds the sun is nearly overhead and a small canopy does the work; shade for hot climates covers it, and shading windows to cut cooling costs covers the low morning and evening sun on the house. For the choice between the three big shades, see shade sail, awning or pergola, how to install a shade sail and how to choose a patio umbrella.

What the game leaves out

Each city is a single point near its center, from GeoNames, and the horizon is flat: hills, buildings and trees are left out. The sun's position is its center, from NOAA's solar position equations, which NOAA states are theoretically accurate to within a minute for sunrise and sunset between 72° north and south; this site checks them against the US Naval Observatory's figures. Times are on the place's own clock, to five minutes, in the year of the puzzle. Direction is from true north, not a compass's magnetic north.

Sources: NOAA Global Monitoring Laboratory, solar calculator details (the equations, their accuracy and the refraction correction); NASA, Earth fact sheet (obliquity 23.44°); US Naval Observatory, seasons for 2026; equation of time and Arctic Circle (Wikipedia); places from GeoNames (CC BY 4.0); NIST Handbook 44, Appendix C (1 foot = 0.3048 meter exactly). The noon altitudes, solar noon times, sunrise and sunset, the equation of time's range and the score table are this game's own calculations.