Did Apple create an entirely new typeface for the Apple Watch? Did they customize something existing? To me it looks like it was inspired by DIN and given a very tall x-height, but I see influence from Roboto in there as well.
Whatever it is, itâ€™s grotesque.
Seriously though, DIN does look close but for its square tittles and punctuation marks and not getting the 9â€™s right.
I fancy Aktiv Grotesk for a closer match on the numbers, but itâ€™s just not â€˜squareâ€™ enough and again lacks round tittles, etc.
UPDATE: Apple did indeed create their own typeface for the font: http://www.apple.com/watch/technology/#familiar
We even developed a new typeface to maximize legibility.
According to the Apple Watch HIGs, it's a new font called San Francisco, and it comes in two flavors:
Choose the San Francisco Text font for text that is 19 points or smaller. Choose the San Francisco Display font for text that is 20 points or larger.