Here's what you can expect from your Apple Watch and watchOS.

watchOS 2 officially has a shipping date: We'll see it September 16. And there will be some new Apple Watch models and bands this fall, too. Here's everything we know about the new Apple Watch models and operating system, for your reading (and salivating) pleasure.

Hold up, what's watchOS?

As OS X is to the Mac, and iOS is to the iPhone and iPad, watch OS is to the Apple Watch. It's the operating system and underlying software responsible for showcasing your clock face, powering notifications, launching and running apps, and pretty much everything you do on the Watch.

iOS 9. OS X. Why is watchOS lower-case without a space?

Same reason iOS has a lowercase i without a space? Probably to make our brains explode.

So when are we getting it?

September 16! Get your downloading fingers ready.

We usually get new iPhones with a new version of iOS. Are we going to get new Apple Watches with watchOS 2?

Sort of. There's no new internal Apple Watch hardware, but the Sport models are getting two new hues: rose gold (really more of a bright pink) and gold anodization, in both 38mm and 42mm. The steel Watch model is also getting one new entry: One paired with a a Product RED band.

Apple's new models will ship starting September 9.

There's also the fashion angle: Apple has partnered with Hermès to introduce three new Watch and leather band combinations. Price and ship date is currently unknown, but I'd expect something in the low-to-mid four figures.

What about new bands? I want more pretty things!

You're in luck! Apple has expanded its Sport band lineup to include darker colors like midnight blue and more muted greys and pinks. These, too, will ship September 9.

So I hear there are some new clock face options?

Correct! In watchOS 2, you'll see the return of clock face options shown off briefly at the original Apple Watch event: Timelapse, Photo, and Photo Album.

Sadly, they seem to be limited to displaying the time; if you want additional complications in the fall with watchOS 2, you'll probably want to stick with one of the other clock faces.

Timelapse offers you a 24 hour timelapse of five locations around the world: Hong Kong, China; London, England; Mack Lake, Michigan; New York City, New York; and Shanghai, China. You just pick the timelapse you want, and it displays when you raise your wrist or turn on the watch.

Photo lets you pick a specific image from the Photos app to display whenever you enable your watch, while Photo Album rotates through all images from your Apple Watch-synced album—you'll see a different picture every time you raise your wrist.

What else is new on the clock face?

Not only are there new clock faces coming in watchOS 2, but you'll also be able to add custom third-party complications to your existing clock faces. With these complications, you'll be able to check your flight info or step count without launching Glances or the app itself.

If your watch is charging on its side, you'll also get the new Nightstand mode in watchOS 2; this lets you view the time and set/silence alarms without having to squint sideways to try and read your clock face.

And let's not forget my favorite new clock face feature: TIME TRAVEL.

Hold up, my watch can travel through time?!

Well, sort of! In watchOS 1, you could turn the Digital Crown when you were on the Solar or Astronomy clock faces to move through days, weeks, and months as shown by the Sun, Moon, Earth, or Solar System.

With watchOS 2, Apple has made this perk a bit more functional: On any clock face that features complications, spinning the Digital Crown will let you rewind or fast-forward through the previous or next 48 hours to see what's happened—and what you still have in store.

This will even work for third-party complications, so you can see if your electric car will be charged in time to drive it to the airport for an upcoming flight, for example. Apple also uses news headlines as an example — you can turn the Digital Crown counter-clockwise to catch up on complication headlines you might have missed. And when you're done time traveling, just press the Digital Crown to return to the current time.

Time Travel works on the concept of a timeline, which means the app powering the complication provides a list of events for the clock face to show. If you try to go back further than the timeline allows, the complication will cease changing and fade to gray.

Also, as mentioned during the keynote, Time Travel won't work with the stock complication, because science.

What kinds of things could I see as an app complication?

Apple gave all sorts of examples during various keynotes and on its website, including the charge time for your electric vehicle, your flight status, HomeKit device activation, sports scores, and the like.

Third-party developers will have access to five different sizes and styles of complication, including those that just display text, imagery, or a combination of both.

How does Nightstand mode work?

If you don't have a fancy charging stand for your Apple Watch and instead prefer to lay it on its side, the company has created a new clock face specifically for this purpose.

With watchOS 2, when you charge your Apple Watch on its side, Nightstand mode activates. The display rotates automatically; it will show any information horizontally when you press the screen, Digital Crown, or Side button. When the display is lit up, you'll see the time, date, and any alarm set in big, bright green letters and numbers.

And if you have an alarm set, when it goes off, you can use the side button to turn it off, and the Digital Crown to snooze for ten minutes.

Is it true? Are real apps coming to the Apple Watch?

Our long national "processing" spinner nightmare should be soon over, yes! With watchOS 2, app extensions are moving from living partially on your iPhone to living completely on your Apple Watch. Your watch apps will still communicate with your iPhone to pull up data, but they should work much more expediently and — better yet — have more functionality.

So what's the difference between a native app and an Apple Watch extension?

Currently, your third-party Apple Watch apps are split in two. The interface lives on your Apple Watch, but the logic that drives the interface lives on your iPhone. So, whenever you launch one, your iPhone has to push not just he data but all of the processing over to your watch for you to use them. This is why you may see the slow "processing" spinner while your app loads, and why your app stops working if you lose connection with your phone.

In watchOS 2, the logic for the app extension moves over to join the interface on the Apple Watch itself. This way, your third-party apps will launch more quickly, and they only have to refresh their data—rather than processing and assets—from your iPhone or from iCloud.

Native watch apps also have access to sensors and buttons that the original version WatchKit extensions did not: Come the fall, third-party apps will be able to hook in to the Digital Crown, accelerometer, your heart rate sensors, and the Taptic Engine. They'll also be able to view and display video and audio; record and play back audio messages; and display animations.

So developers can tap into my heart rate data?

Yup! But only if you give them permission to, first. If you like working out with apps like Strava, or you (like me) have a hobby that Apple's Workout app can't quite track, this will be a huge boon for your daily exercise tracking.

Wait, access to the Taptic Engine? Am I going to have to deal with apps buzzing my wrist all the time now?

Depends on the app, but probably not: Though third-party apps have access to the Taptic Engine, they'll be limited to a subset of haptic buzzes and clicks. And if an app annoys you with its buzzing too much, you can also always disable or delete it.

The Apple Watch screen is pretty small. What's video going to look like?

Pretty small! But it should be visible enough. Video on the Apple Watch will play back at 208-by-260 pixels (fullscreen) or 320-by-180 (letterboxed), at 32kbps audio AAC routed through Bluetooth headphones.

In other words, there was a reason Apple went with Vine for the video segment.

How is all this going to affect my watch's battery life?

To be determined. Heavy animations, graphics, taptics, and heart rate checks already put some drain on your Apple Watch battery currently; with third-party apps having access to your sensors, you may find that, come the fall, your watch runs out of battery sooner. Or you may not! It really depends on how well-built the apps in question are, and what you use your watch to do.

What new features are coming to Apple's default apps?

There are a couple of awesome new perks. Mail becomes a full-fledged citizen on the Apple Watch and gets a "Reply to Email" option on both notifications and in the Watch app itself; the reply screen looks almost identical to your Messages reply screen, offering dictation, emoji, or preset replies.

iOS 9's transit information will also appear on the Apple Watch, letting you view subway maps, bus schedules, and get walking and transit directions for any of the Transit-supported cities.

Will I really be able to send sketches to more than 12 friends now?

You will! Apple is introducing multiple Friends screens to the interface, allowing you to name each screen and add twelve separate friends to every one; you'll also be able to add friends directly on the watch, rather than having to use the Apple Watch app on your iPhone.

Once you've added those friends, you'll be able to do even more with Apple's Digital Touch sketching feature: The company has opened up the color palette to let you draw with multiple colors before your drawing vanishes off to your friend's Apple Watch.

What's new with Apple Pay and the Apple Watch?

Come the fall, watchOS 2 will get the same loyalty card improvements to Apple Pay as the iPhone: You'll be able to use store credit cards, rewards cards, and more—all right from your watch. If you're a Discover Card user, you'll also be able to add those cards to Apple Pay.

Will Siri be able to understand more commands?

Thankfully, yes. A few of the Handoff growing pains disappear with watchOS 2, letting you do just a bit more on your Apple Watch. You can start workouts, open glances, get transit directions, look up dictionary words, calculate tips, launch HomeKit devices, and more.

What's this I've heard about Activation Lock coming to the wrist?

When the Apple Watch first launched, it didn't ship with Activation Lock—the company's iPhone security feature that requires your Apple ID and password when trying to erase your device, reactivate it, or remove tracking. With watchOS 2, however, your Apple Watch will gain the same protective features, keeping would-be thieves from getting at your data or reselling your device.

Any other questions?

Got a question about the Apple Watch 2.0 software update that we didn't answer? Fire it off in the comments and we'll try to address it.