Adam's Peak Season & Sri Pada Sunrise Planner

Every page currently ranking for “adam's peak season” quotes a vague “December to May” and a guessed “start at 2 a.m.” Neither is a date. This tool computes both, in five steps.

1. The season window

Sri Lanka Tourism's own description of Sri Pada puts the season between December and May, with January to March the busiest stretch, and the object of the climb being to stand on the summit at sunrise for the triangular shadow. The two ends are full-moon Poya days: Unduvap Poya in December opens it and Vesak Poyathe following May closes it. Both come from this site's existing Poya engine, which implements the Meeus full-moon series and already knows about adhi (doubled) lunar months — there is no second copy of the Poya table in this tool.

Two selection rules matter in an adhi year. When December holds two full moons the earlierone opens the season, so it still begins in early December instead of on New Year's Eve — December 2028 is that case. When May holds two, the later one closes it, because that is the moon the Vesak holiday is gazetted on. May 2026 was that case, and getting it backwards would have closed the 2025/26 season on 1 May and told a month of pilgrims it was over while it was still running.

Finally the computed moon is reconciled against the gazetted Holidays list. If a gazetted Poya falls within two days of the astronomical full moon, the gazetted date wins and the full-moon date is printed beside it. This is not cosmetic: the 2026/27 season opens on the gazetted Wed 23 Dec 2026 while the full moon is Thu 24 Dec 2026, and closes on the gazetted Wed 19 May 2027 against a full moon on Thu 20 May 2027. Matching is done on proximity rather than on the Poya's name, because the 2026 list names the wrong moon “Vesak”.

2. How much altitude buys you

From the summit you are looking down at the horizon, so the sun clears it earlier than it would at sea level. The drop is the horizon dip, and the standard nautical formula — which already folds in terrestrial refraction — is

dip(arcmin) = 1.76 × √h(metres)

At h = 2,243 m: √2243 = 47.36, so dip = 83.35′ = 1.3892°. As a check, the purely geometric dip from the Earth's radius, acos(R / (R + h)), comes out at 1.5201°, matching the textbook 1.93 × √h rule to within 12 arcseconds. The 0.131° gap between the geometric and nautical values is the refraction allowance the 1.76 coefficient carries.

3. The summit zenith

Ordinary sunrise is computed at a solar zenith of 90.833° — 0.833° covering atmospheric refraction and the sun's own semi-diameter. Add the dip:

summit sunrise zenith = 90.833 + 1.3892 = 92.2222°
summit civil dawn zenith = 96.000 + 1.3892 = 97.3892°

Civil dawn is the shadow window opening: the sky is light enough for the triangle to form on the cloud below, but the sun has not risen.

4. The sunrise time

Solar declination, the equation of time and solar noon come from the NOAA solar algorithm evaluated at the summit's coordinates, 6.8096° N 80.4994° E from the Survey Department's 1:50,000 sheet. The hour angle at the target zenith then gives the time:

H = acos( (cos Z − sin φ · sin δ) / (cos φ · cos δ) )
sunrise = solar noon − 4 × H

This is the same code path the site's sunrise/sunset tool already uses, so there is no second solar implementation to drift. The altitude bonus is cross-checked a second, unrelated way: divide the dip by the rate the sun's altitude changes as it rises, 15°/h × cos φ × sin(azimuth). For 10 January 2027 the hour-angle solution gives 6.03 minutes earlier and the altitude-rate approximation gives 6.04 — they agree to 0.5 seconds.

5. The start time

Target arrival is summit sunrise minus your margin. Departure is that minus the climb time for your route and pace. Where the answer lands before midnight the tool rolls the date back and labels it, because that is the single case readers get wrong: a Palabaddala climb for a April morning starts the previous evening. The route distances, ascents and time ranges are the one set of figures here that is neither gazetted nor computed — they are typical walking times from the standard route descriptions, and the table says so rather than dressing them up as an official standard.

Distances and ascent from the standard route descriptions; climb times are typical walking times at each pace, not an official standard.

Only Nallathanniya and Palabaddala carry the lit pilgrim stairway in season. The “5,500 steps” figure quoted for Nallathanniya is indicative — it has never been surveyed.

• Sri Lanka Tourism Promotion Bureau — Adam's Peak
• Department of Government Printing — Holidays Gazette
• Survey Department of Sri Lanka — 1:50,000 topographic series
• NOAA Global Monitoring Laboratory — solar calculation details
• Department of Meteorology — weather warnings — check before you travel

The Poya full moons come from Jean Meeus, Astronomical Algorithms (2nd ed., ch. 49) via this site's moon phase and Poya calculator, and the solar times from the NOAA algorithm via the sunrise and sunset tool. The horizon-dip formula is from the Explanatory Supplement to the Astronomical Almanac, 3rd ed., §7.2. Route figures and the gazette reconciliation were last checked on 2026-09-26.