What time to leave camp so you don't hike in the dark
Two separate questions, both worth answering before you leave camp. First: given how many hours today's hike will take, what time do you need to start walking? Second: even if you leave on time, does the day actually end before the sun does? Far answers both from the same target arrival time, not a single vague rule of thumb.
The formulas
Both assume a target camp-arrival time — 5:00 PM by default, whatever you set it to.
Sunset is calculated at the trailhead's own local time zone, not the device viewing the plan — a hiker planning a Yukon trip from Toronto needs the Yukon's real sunset, not their own.
Worked example: leave-by time
Target arrival fixed at 5:00 PM. Only the day's hiking hours change.
| Hiking hours | Leave by |
|---|---|
| 4 hours | 1:00 PM |
| 9 hours | 8:00 AM |
| 12 hours | 5:00 AM |
| 14 hours | Long day — consider splitting further |
Below a 4:00 AM leave-by time, Far stops naming a clock time — the honest answer at that point is a shorter day, not a technically-correct pre-dawn start.
Worked example: daylight margin
Target arrival still 5:00 PM. Only the trailhead's real sunset time changes.
| Sunset | Margin | Result |
|---|---|---|
| 9:05 PM | +245 min | Clear |
| 5:45 PM | +45 min | Warn — tight daylight |
| 4:40 PM | −20 min | Danger — arrives after dark |
Under 60 minutes of margin warns; a negative margin — arriving after the sun is already down — is treated as a real danger, not just a warning.
Why leave-by is checked first
Far only checks daylight margin on a day whose leave-by time is already reasonable. An unreasonable day — one that would need leaving before 4:00 AM to make the target arrival — gets exactly one finding, not two: fix the day length first, and the after-dark question resolves itself once it's split.
Limitations
- Both formulas use the trailhead's sunset, not the actual camp's — real terrain, tree canopy, and valley shadow can make it functionally dark earlier than the calculated sunset.
- 5:00 PM is a planning default, not a rule — a party comfortable making camp after dark with headlamps can set a later target.
- Hiking hours themselves come from Far's own pack-weight-and-terrain estimate — see the hiking-time guide for how that number is built.
Formula current as of 2026-07-21. Source: Far's own itinerary rules engine, applied identically in the app.