Guide
Every setting, how the numbers are worked out, and what the screen shows. Change settings in the Connect IQ app (SUMMIT HUD › Settings); everything works without changing any.
SUMMIT HUD times the way back from your day so far. It can’t see the weather, the snow, the terrain ahead or how tired you’ll be: when any of those turns against you, turn earlier than it says.
Your day
| Setting | Default | Guidance |
|---|---|---|
| Activity | Hike, mountaineering, trail | Or ski touring: the way back is then a ski descent (see below). |
| Summit or goal altitude | 0 (none) | In your watch’s elevation units. Adds the summit check: height and time to the top, when you’d top out and when you’d be back if you go for it, and a prompt when you reach it. |
| Hard turnaround time | Empty | A clock time you’ve agreed before you left: 13:00, 1:00p, 12:30pm. SUMMIT HUD holds you to it or to daylight, whichever comes first. |
| Must be back by | Empty (by daylight) | For a last bus, a hut’s dinner or a ferry: 17:30. Replaces daylight as the deadline. |
| Way back | The same way | Out and back: the way back is the way out reversed. For loops and traverses, choose the shortest way: the straight line to the start × 1.3, and the height to lose or gain. |
Daylight
| Setting | Default | Guidance |
|---|---|---|
| Daylight ends at | Sunset | Or civil dusk, when the sun is 6° down: the end of usable light without a headlamp on open ground, about 25 to 40 minutes after sunset at mid latitudes. In forest or on steep ground, keep sunset. |
| Safety buffer before dark | 30 min | Your deadline is dark minus this. More for a first visit, unknown descents or a group. |
Ski touring
| Setting | Default | Guidance |
|---|---|---|
| Ski descent speed | 1000 m an hour | Vertical metres an hour, stops and transitions in. Lower it for bad snow, tired legs, poor light or a group; raise it only for slopes you know and ski fast. |
Battery and alerts
| Setting | Default | Guidance |
|---|---|---|
| Battery % when back | 20% | The battery line turns red, and the watch buzzes once an hour, when today’s drain would leave you under it at the start. |
| Alerts | On | Vibration and full-screen prompts: 30 minutes before the turnaround, at it (then every 10 minutes), at the summit, when dark is near or passed, and for the battery. Enable SUMMIT HUD under the activity’s Alerts › Connect IQ to see them full screen. |
The screen
- Top: the activity (or the summit and the height to it) and the time out; the clock.
- The big number: going up, the time left to turn around; after the turn, the margin to your deadline. Green, amber under 30 minutes, red past it.
- The pair: when you’d be back at the start, and the margin to dark (after the turn: the time left and the margin to dark).
- Below: altitude, climbing or descending rate, the day’s climb, descent and distance.
- The outlook line: the summit check when a summit is set, otherwise sunset or dusk and the light left.
- The bottom line: battery now and when you’re back, in red under your reserve.
- The ring: the day from the start to dark around the bezel, with ticks for the deadline (red), the turnaround (amber) and when you’d be back (white). Past dark, the whole ring is red.
How the numbers are worked out
| Effort | Distance + climb × 10 + descent × 5: 1 km of trail = 100 m of climb = 200 m of descent, the Swiss hiking rule (SAC). Climb and descent are the watch’s own totals. |
| Pace | Effort per hour from your day so far, breaks included, the last hour blended half and half with the whole day. |
| The way back | Out and back: what went up comes down, what came down goes up, timed at your pace. The shortest way: the straight line to the start × 1.3 and the height difference. Ski touring: the descent at your ski speed, flats at 15 km/h, plus 10 minutes to rip skins. |
| Deadline | Must-be-back-by if set, otherwise sunset or civil dusk at your start minus the safety buffer. Sunset and dusk come from the USNO sunrise equation, on the watch. |
| Latest turnaround | Slack = deadline − back if you turned now. Over the last 10 minutes the way back grew by g minutes per minute; each minute further spends 1 + g of slack, so the latest turnaround is now + slack ÷ (1 + g). A hard turnaround time wins when it’s earlier. |
| Summit | Height to go × 4 of trail (a 25% average grade) at your climbing pace; the extra is added to the way back. |
| Turned | LAP, or by itself once you’re 500 m or more out and the distance to the start is down by a fifth and by 300 m; the turn is dated back to your farthest point. |
| Battery | The drop over the last hour × the hours until you’re back. |
An example. You’re 2 hours out: 7 km with 700 m of climb, 7 + 7 = 14 effort-km, so 7 an hour. The way back is 7 km and 700 m of descent: 7 + 3.5 = 10.5 effort-km, 1:30. Dark is at 18:40, your buffer 30 minutes, so the deadline is 18:10; it’s 13:40, so you’d be back at 15:10 with 3 hours of slack. On the steep part ahead, the way back grows by half a minute for every minute you go on (g = 0.5: descent counts half as much as climb), so the latest turnaround is 13:40 + 3:00 ÷ 1.5 = 15:40, two hours away, not three.
Prompts
- Turn in 30 min: once, with the clock time to turn by.
- Turn around: at the turnaround, then every 10 minutes until you turn.
- Summit: when you get within 15 m of the altitude you set, with the time you have to leave by.
- Dark soon: once on the way back, when you’d be back less than 30 minutes before dark.
- After dark: on the way back when you’d be back after dark, every 15 minutes.
- Battery: at most once an hour, when you’d be back under your reserve.
- Turned: when you press LAP (a second LAP within a minute undoes it).
If the field gets a smaller slot
In a layout with more than one field, SUMMIT HUD shows the big number and the line under it. Use the one-field layout for the full view.
In your activity file
SUMMIT HUD records two Connect IQ fields with your activity: the turnaround margin and the daylight margin, so you can see afterwards how close the day was.
General guidance, not safety advice. The Swiss hiking rule (SAC) and the USNO sunrise equation are public; the rest is SUMMIT HUD’s own.