GPS Altimeter App — read the mountain, even without signal.
// gps altimeter · barometer · compass · offline · iPhone & Apple Watch
A GPS altimeter app for iPhone that reads your altitude, atmospheric pressure and bearing straight from the device's own sensors — fully offline. A barometer-based weather forecast, an AI trail assistant and five home-screen widgets make Peak the complete hiking companion, from sea level to summit.
Screens
From the trailhead to the rim.
Real screenshots from the App Store. The altimeter view at the top was captured in Tijarafe, on our home island of La Palma.
What it does
GPS altimeter & barometer — a full instrument panel.
Everything Peak measures comes from sensors already inside the iPhone — so the core keeps working with no internet, deep in the valley or up on the rim.
GPS altimeter
Precise altitude in metres or feet, anywhere on Earth, paired with a compass and a sunrise & sunset calculator. Read your exact elevation at a glance, even off-grid.
Barometer & forecast
Live atmospheric pressure monitoring with a barometer-based weather forecast. The weather icon updates from real barometric readings, so you anticipate a turn before it arrives.
AI trail assistant
A ChatGPT-powered guide reads your context and suggests hikes and things to do nearby. From Tijarafe, La Palma, it suggested watching the sunset at Mirador El Time.
Five home-screen widgets
Altitude, sunrise & sunset, location, barometer and weather — each as a dedicated widget. Keep the readings you care about on the Home Screen without opening the app.
Speedometer & steps
A built-in speedometer shows real-time speed for hikes and bike rides, while a step counter tracks steps and distance. Your exact longitude and latitude are always one tap away.
Off-grid walkie-talkie
Send and receive real-time voice messages with nearby users — no internet needed. Quick local comms for the group when you're out on the trail and the bars are gone.
The details
Altimeter app specs & privacy.
Sensor-driven, privacy-first, and reliable in remote locations. No internet connection required for the core readings.
Offline & private
Peak is designed to work fully offline using the device's own sensors, so it stays reliable in remote locations where there's no coverage at all.
Customizable metric and imperial units, a clean and intuitive interface, full Apple Watch support, and an updated privacy posture in the latest release.
The collection
More instruments.
Peak is one of five Avo apps for sea, trail and summit — each built around a single job, each working when the bars disappear.
FAQ
GPS altimeter app — questions, answered.
Everything you want to know before downloading Peak, the offline GPS altimeter app for iPhone.
Take it to the summit
Read the mountain, offline.
Free to start, no account, no signal required. Altitude, pressure and a trail guide — all from your iPhone's own sensors.