Boost Weather
One read on the air before you drive. Four inputs become eleven air values and one verdict for your car: Green, Yellow, or Red, with the reason.
Out now for iPhone and Apple Watch.
What Boost Weather Does
A native iPhone and Apple Watch app that turns the weather where you are into a pre-drive air check for performance cars.
One verdict, with the reason
Every read ends in Green, Yellow, or Red and a one-line reason such as "Good air", "Hot air: thin knock margin", or "Not a pull day". Tap the verdict to see every check your profile ran: your value against each threshold, what fired, and why.
Car profiles with your thresholds
Start from a naturally aspirated or boosted template, then edit the temperature bands, dew point lines, and charge temp limits to match what you know about your car. The verdict applies to the active profile, and switching cars is one tap.
A forecast graded for your car
A seven-day card under the verdict shows each day from low to high, colored by what the air will read at its warmest hour for your profile. Tap a day for the reason and range, or open it hour by hour.
Snapshots you can hand to a tuner
Capture the air as it is right now and share it as a one-line air read, as text, or as JSON. Snapshots keep every value exactly as captured, so a dyno day or a track session has a record.
Four Inputs, Eleven Values
Temperature, dew point, station pressure, and elevation go in. Everything below is computed on your phone from published formulas, and every number shows where it came from and how old it is.
Density and altitude
- Density altitude
- Relative air density
- Air density in kg/m³
- Pressure altitude and altimeter setting
Moisture
- Relative humidity
- Dew point, to tenths of a degree
- Specific humidity in grains per pound or g/kg
Pressure
- Station pressure in inHg or hPa
- The same pressure in psi, so the ECU baro cross-check is always visible
- Optional live barometer reading from the phone
Corrections
- SAE J1349 and STD dyno correction factors
- Predicted cruise charge temp for boosted profiles
- Optional ambient and highway offsets set from your own dash readings
Imperial or metric, your choice. Manual mode lets you type all four inputs yourself, always badged so a manual read is never mistaken for a live one.
On Your Wrist and Your Lock Screen
The same verdict and tiles, wherever you glance first.
Apple Watch
A standalone watch app with the verdict, all eleven tiles, the profile picker, and one-tap snapshots. Readings are independent, so the watch works without the phone in your pocket.
Complications and widgets
One configurable widget: each complication or Lock Screen slot picks a metric and tints it by its grade. Put density altitude on your watch face and the verdict on your Lock Screen, or the other way around.
Read the air somewhere else
Save a track, a city, or a ZIP code as a custom location and switch to it in one tap. A car profile can carry its own place, so picking the track car brings the track with it. Widgets follow along.
Works offline
The last reading stays visible with its age. After three hours it is marked stale, and after twelve the verdict card says "No recent read" instead of pretending.
Private by Construction
No accounts, no analytics, no trackers, no ads. Boost Weather is a one-time purchase with no subscription. Your location is used only to fetch the weather where you are and to read your elevation, and it is never stored or shared. The barometer stays off until you turn it on.
Weather data comes from Apple Weather. Car profiles, snapshots, and settings live on your device and sync between your iPhone and Apple Watch through your own iCloud account. We never see them. Deleting the app removes them.
Our privacy policy covers Boost Weather in detail, and the terms of service set out how it is meant to be used.
The Verdict Describes the Air, Never the Car
Boost Weather reads the atmosphere. It does not read your engine, your tune, or your tires, and it has no opinion about whether you should drive. A car profile is your own thresholds for your own car, written down so the app can compare today's air against them. Green, Yellow, and Red say what the air is doing. What you do with that is up to you.
Boost Weather Support
Questions, feedback, or trouble with Boost Weather? Send us a message through our contact form and we'll get back to you within a business day.