---
title: "Trail Day Planner: Turnaround Time & Sunset | Summit Cabin"
description: "Plan a hiking day: walking times with breaks, a turnaround time that gets you back before sunset (worked out offline), a checklist and a printable plan."
url: https://summitcabin.top/trail-day-planner/
---

# Trail day planner

Plan the day around the daylight. Set your start time, pace and breaks; we work out when you reach the top, the latest time to turn back, and whether you will be down before sunset. Then tick off the checklist and print a plan for someone at home.

## How the plan is built

Walking times come from the [hiking time calculator](https://summitcabin.top/): Naismith's rule with Langmuir's corrections, Tobler's hiking function, or the longer of the two. For an out-and-back, the way back is the way out reversed, so your climb becomes descent. Short breaks are added after each stretch of walking you choose, and the long stop sits at the turnaround, or halfway through a loop.

The **latest time to turn back** is sunset, minus your safety margin, minus the time the return will take with its breaks. Agree it before you start and turn round when it comes, even short of the top.

## Sunset, worked out offline

Sunrise, sunset and civil dusk are calculated in your browser with the equations behind NOAA's solar calculator, which NOAA describes as accurate to about a minute between 72° north and south. Times assume a flat horizon: the sun drops behind ridges sooner, and civil dusk, when the sun is 6° below the horizon, is roughly when you need a headlamp in the open.

## Checklist and trip plan

The checklist follows the ten essentials as the US National Park Service groups them, and the NPS advises telling someone where you are going and when to expect you back. Print the plan or copy it into a message for them. Ticks, your own items and the trip details are saved in this browser only.

## Sources

- NOAA Global Monitoring Laboratory. [Solar calculation details](https://gml.noaa.gov/grad/solcalc/calcdetails.html) (based on Meeus J, *Astronomical Algorithms*).
- US Naval Observatory. [Rise, set, and twilight definitions](https://aa.usno.navy.mil/faq/RST_defs).
- US National Park Service. [Ten essentials](https://www.nps.gov/articles/10essentials.htm).

## Questions

**Why is my sunset different from the weather app?**

Apps differ by a minute or two in how they round and which point they use. A larger gap usually means the time zone or the coordinates are wrong: check that the longitude is negative west of Greenwich.

**What if the sun never sets?**

Near the poles in summer the planner tells you so, and in winter it shows civil twilight if the sun does not rise. Plan with extra care then.

**Does it use my location?**

No. The page never asks for your location; you type coordinates, and the maths runs on your device.