Boost Weather: Air Density

Density altitude, air density, and intake charge temp for your car, read from Apple Weather where you are and graded Green, Yellow, or Red against your own thresholds. One read on the air before you drive.

Boost Weather takes four inputs, temperature, dew point, station pressure, and elevation, and computes seven more values on your phone: density altitude, relative air density, air density, humidity, specific humidity, altimeter, and the correction factor a dyno would apply. Then it grades them against a car profile and gives one verdict with the reason on the card. When the air clears every yellow and red line, the headline says what kind of read it is: Thick air, with a blue Strong pill, when the air is dense; the temperature in a word, such as Mild air; or the note that trims it, such as Warm air or Very humid. The verdict describes the air, never the car.

RADAR
Tap the map button on the verdict card for the National Weather Service radar around where you're reading the air, or around your custom location. Press play to run about the last two hours of scans and see which way the rain is moving, or drag the timeline to stop on one. Radar covers the United States, so the button shows only there.

CAR PROFILES
Start from two templates, one for forced induction and one for naturally aspirated, and edit every line: the yellow and red temperature bands, dew point and humidity lines, a tire floor, and for a boosted car the charge temperature offset and the ideal, ceiling, and knock lines. The editor lists typical offsets by intercooler type and lines by fuel, so you can set yours without guessing.

OFFSETS
The air over sunlit pavement reads warmer than a weather station's number taken over grass. Type what your dash shows and the difference becomes the ambient offset, with a separate highway line for Drive mode. Drive mode watches your GPS speed while the app is open and switches to the highway line above the speed you set. It stops the moment the app leaves the screen and never tracks in the background, and the speed is never stored or sent.

WHY THIS READ
Tap the question mark on the verdict to see every check your profile ran: your value against each threshold, what fired, and why. On a device with Apple Intelligence turned on, the page opens with a short analysis written on your device from those checks. It never changes the verdict, and you can turn it off in Settings.

SURFACE
When rain, snow, ice, or a storm is falling where you read the air, an orange pill beside the verdict says so: Wet surface, Snow, Ice risk, or Storm. Tap through to see what it means for grip and the hour it should clear.

FORECAST
A seven-day card under the verdict, one bar per day from the low to the high, colored by what the air will read at the day's warmest hour for your profile. Open any day for the hours.

APPLE WATCH AND WIDGETS
The watch app shows the verdict, the tiles, the forecast, a profile picker, and one-tap snapshots. Home Screen and Lock Screen widgets and watch complications each pick a metric, so a face can hold several. Between refreshes they follow the hourly forecast, so the morning shows the morning's air.

MORE
- Snapshots you can share with a tuner as a one-line summary, as text, or as JSON.
- Manual mode for entering all four values yourself, always badged.
- Custom locations: save a track, a city, or a ZIP code and read the air there.
- Imperial or metric, your choice.
- Works offline: the last reading stays visible with its age.
- No account, no sign-in, no ads, no analytics. Your location is used to get the weather where you are, read your elevation, and record where each reading was taken. It is never sent to JonesLabs.

Read the air. Then go drive.

Weather data provided by Apple Weather. Radar from the National Weather Service.
Terms of use: https://joneslabs.dev/terms#boostwx