Enter the forecast (direction the wind comes FROM, sustained speed). The ghost eases into headwinds and speeds up with tailwinds, weighted by how exposed each stretch is. Same finish time.
Needs a connection, once. On race morning the start screen also offers it by itself (one look at the forecast, never during the run).
Seconds the ghost loses at each of the 15 aid stations (drinking). 0 = the ghost runs through.
Water at every station, Krono electrolytes at all but km 3.2, toilets at every one (runner's guide).
For a phone in a pocket or an armband. During the run the screen goes black (black pixels on the iPhone screen use almost no power) and the map stops drawing, but GPS and the voice keep going. Tap the screen to look for 12 s; when it goes black again, the run settings close. Also in the run settings (hold the gear 5 s).
Do not lock the phone with the side button: iOS freezes web apps while the phone is locked, so there is no GPS and no voice until you unlock it. The app then catches up and says the gap.
LIVE starts the clock at this time, then switches to your chip time as you cross the start line, so a gun a few seconds early or late does not matter. Change it only if the start is delayed by minutes.
Try the pacer on a real run: one way, from home to DKN or back.
LIVE rehearsal runs race-day LIVE mode on this route: a countdown, a “Go!” at the gun (there is no real one), then the switch to chip time as you cross a start line 30 m along the route. Stand at the start of the route.
Two things to turn on. Tap a button, then choose Allow when the iPhone asks.
Later on: the buttons at the top of the map, or Help → Location.