Sometimes an app is so nicely done for a particular discipline that it becomes, perhaps, the quintessential app of its kind. Nav Clock is one of those in my opinion. No pilot, astronomer, photographer, journalist, hiker or anyone interested in time and weather should be without it.
Nav Clock was one of the earliest apps available in the Apple App Store, and it has been a staple of mine ever since. I've occasionally referred to it in other articles, but it's high time it got its own place in the TMO reviews showcase.
iPhone display, portrait.
In short, Nav Clock tells you just about everything one can know about a location's geographic position, time and weather. It's a Universal app for all iOS devices and suffers very little going from the iPad down to the screen size of an iPhone/iPod touch. (Of course, those small screen versions came first.)
Time
This app has a particularly rich set of settings for time and location. Astronomers will like the options for GMT, Julian Date (JD), MJD, JDN, RJD and Solar noon and well as WGS84 coordinates. Latitude and Longitude can be derived from iOS Location Services or you can enter you own, in either deg-min-sec or deg-min.M.
Extensive Settings. This one is Time and Date.
The time is extracted from the iOS Device internal clock. Fortunately, iOS devices without access to time derived from a cell tower, for example, a Wi-Fi iPad or iPod touch, now use an NTP server. See "What Time is it? Your iPad & iOS 5 Finally Knows."
One thing pilots and astronomers will appreciate is the listing of not just the local sunrise and sunset times but also the beginning and ending of Civil Twilight -- when the sun is 6 degrees below the horizon.
There is also an auto-lock feature to prevent the display from sleeping when continuous monitoring of the time is desired. (Say, at the observatory.) For convenience, the brightness control is right there on the main screen if you just tap it.
Location
If you're using an iPhone with GPS, you'll not only get very good geographical coordinates, but also elevation above mean sea level, plus an estimate of the accuracy. Also included is course and speed, good for hikers and skiers.
iPad in landscape mode.
Without GPS, Nav Clock will obtain your estimated position from iOS Location Services. There is an option to display your general geographic location by name shown above, as well as display the latitude and longitude.
Weather
Weather data is pulled from NOAA's Aviation Digital Data Service (ADDS) servers. The server being used will be displayed at the bottom. You'll have, at your finger tips, the local wind, visibility, pressure, humidity, dew point and wind chill. (English or metric.) You can display the local temperature in both Fahrenheit and Celsius at the same time if desired.
In general, you can switch between the English and metric system of units. But even if you select English units overall, you can opt to display wind speeds in meters/second.
iPhone, sky at sunset.
The time of the last weather update, every 15 minutes, is shown at the very bottom. You can also opt for continuous updates of your location instead of every 3 minutes, but that chews up battery power. That, of course, helps greatly for course and speed information.
One of the things I like about the app is that the background graphic reflects the local weather/sky conditions with about 90 original photographs. If the sky is dark, then the background will be dark. There's a neat preference so that after sunset and before sunrise, you can set the text to red (to preserve night vision) or several other high contrast colors like green or blue.
Night time. Optional red text.
System Requirements
Nav Clock is optimized for iOS 6 and iPhone 5. It supports Retina displays and is supported on any iPad, iPhone or iPod touch. Requires iOS 5 or later. There are partial translations for German, Portuguese, Romanian, Russian, Spanish, and Swedish.
Summary
I've had this app on the first page of my iPhone from day one. It's been one of my most often used apps, and I've come to trust the technical accuracy brought to bear by the developer. Also, I've never lost my connection to an ADDS server. I use Nav Clock as a sanity check on other similar apps that I've reviewed.
If you have even an idle interest in local weather, time and location data, with a boatload of customization options, then this app deserves to be on your iDevice's home page. For a buck, it's just plain essential.