Marine Barometer is a barometer sensor interface that is uniquely designed to meet the needs of mariners who rely on accurate atmospheric pressure for weather routing and the evaluation of weather maps. Pressure readings can be manually saved permanently along with the latitude, longitude, and time of the reading. If a sensor offset has been applied, that value is also stored with each recorded pressure. These recorded pressures can then at the navigator's convenience be transferred to the vessel's printed logbook.

The GPS sensor is accessed for latitude and longitude only. The elevation of the sensor (your iOS device that includes a barometer) above sea level must be entered manually. Elevation values from the GPS are not accurate enough for the intended application.

A sliding average of the pressure displayed over the past 14 seconds can be engaged to account for the change in sensor height in the presence of waves and swells at sea so that an accurate sea level pressure can be obtained.

The concept of sea level pressure is explained along with how it is determined from the sensor reading.

Instructions are provided on how to check the calibration of the sensor, and a sensor offset can be applied as needed. Links to sources of accurate sea level pressure are included. Sources of accurate elevation are included for use on land.

The standard units for marine applications are millibars (mb) or hectoPascals (hPa). The main pressure display can also be set to inches of mercury, millimeters of mercury, or kiloPascals. However, because the primary reference pressures that would be used to check the sensor calibration are in mb, the sensor calibration must be set using millibar units.

Reference links are provided for learning more about the tactical use of pressure for weather forecasting and weather map evaluation. Discounts are offered for barometer related reference books.

What’s New

Version 1.1

Improved iPad display.

Ratings and Reviews

4.8 out of 5
17 Ratings

17 Ratings

jalmberg ,

Best in the App Store

I have never taken the time to review an app before, but I am so pleased with this one that I had to stop and write one.

My wife and I are offshore sailors, and I’ve been looking for a really accurate barometer for about a year. I really accurate barometers are really expensive, so I hoped to make do with an iPhone app.

I think I have most of them, at this point, but this is the first one that ticks all the most important boxes.

First, it’s not a black box with hard to understand calibration parameters. It has exactly two, and they are the two obvious and critical ones: altitude and sensor offset. These are the only two required for accurate readings, so I’m not sure why other apps have more. This is a case where more is not better.

Second, it averages the readings. The sensor in the iPhone is pretty jittery so averaging is absolutely necessary.

The result is a simple, accurate barometer that — I hope — will stay accurate over a goodly period of time. I haven’t used it long enough to know if it drifts over time, but I guess that would be the fault of the sensor, not the app.

I intend to track its accuracy over time, with the hope I don’t have to buy one of those $700 barometers!

Well done.

OKC (Ocean Kayak Cowboy) ,

Marine Barometer

Just started looking at this app. Just on the basis of the detailed info it contains, the references it lists and the potential it affords with incredible ease, the publisher should be greatly admired and complemented. App is very well designed and explained and brings this data and science within easy reach of even the more casual user. Many kudos!


Useful utility

Straight forward and nicely organized for the sailor. I can now compare my ships barometer to the barometer in my iPhone


Starpath Corp
19.9 MB

Requires iOS 11.0 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating
Rated 4+
© 2018 Starpath Corporation


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