Hiking Daylight Turnaround Calculator
Derive local sunset, test both hike legs and set a latest turnaround with a daylight buffer. Inputs stay in your browser.
The calculator derives sunset from the trail coordinates, then tests the planned outbound and return legs against the selected safety buffer.
Context matters.
- Enter conservative leg times that include breaks, route-finding and the slowest member of the group.
- Terrain can hide the sun before the geometric sunset. Weather, injury and navigation errors can consume the entire buffer.
- Carry a headlamp and an emergency plan; this tool is a planning check, not a guarantee of safe passage.
Sources & scope
The calculation guide and this source trail show what the result means, where the rule came from and when it was last reviewed. This is source-and-calculation QA, not a claim of medical, legal, tax or other professional review; time-sensitive decisions still belong with the linked authority.
A visible path from input to answer.
Derive local sunset, test both hike legs and set a latest turnaround with a daylight buffer. The page keeps the calculation scope and its limits beside the result so the output can be checked, copied or revisited.
- Read the record. The calculator uses Hike date, Trail latitude, Trail longitude, UTC offset on this date and Planned start time and 3 additional fields supplied in the form.
- Apply the scope. It applies the Global solar/lunar planning — user-provided coordinates and date-specific UTC offset reference and the explicit date, unit and counting conventions shown in the result.
- Expose the checkpoints. Intermediate rows, warnings and timeline events stay visible; the emphasized row identifies the primary checkpoint when one exists.
The calculator derives sunset from the trail coordinates, then tests the planned outbound and return legs against the selected safety buffer.
- Daylight cutoff18:57
- Latest safe turnaround16:57
Calculation purpose: Derive local sunset, test both hike legs and set a latest turnaround with a daylight buffer. This is a general planning reference; local conditions, product instructions or personal records can override the estimate.
Calendar inputs use plain year-month-day semantics. Leap days, month ends, date-pair order and unsupported dates are checked before the result is shown.
Rule set 2.0.0 · Last reviewed 2026-08-20 · Next review due 2027-02-20. The source panel below contains the linked evidence.
What to know before using the result.
What is the latest safe turnaround?
It is sunset minus the entered return-leg time and safety buffer. Turn earlier when terrain, weather, pace or navigation adds uncertainty.
Should I include breaks in the leg estimates?
Yes. Use conservative times that include breaks, route-finding and the slowest person in the group.
Does finishing before sunset mean a hike is safe?
No. Terrain can hide daylight early, and delays can consume the buffer. Carry lighting, navigation and an emergency plan.