I was originally going to put this in a new thread (and it may well have already been covered in this one) but here we go...
The Coldplay website was recently updated to remove the Everyday Life cover and instead the site has reverted to a neutral theme with AHFOD/Kaleidoscope rainbow theming. This is strange because Everyday Life is a recent album, but as we know, Chris Martin has said that there's a new Coldplay album coming 'soon'. This isn't what this post is about, however. It's about the little icons at the top right of the website showing the different stages of the moon. Currently, it is one away from a full circle, a sphere (the next album is thought to be called Music of the Spheres).
It moves frequently (presumably along with the real moon cycles). This screenshot, taken using the Wayback Machine, shows it at the first stage in late July.
Now, while it would be easy to say that when it reaches the second full circle Coldplay would announce the new album, that would be silly. The second full circle has been filled before...
...so it doesn't mean anything in my opinion. Instead, we need to look to the stars - literally. There are four major events to do with the sun, two solstices and two equinoxes. Could an announcement be made on one of these dates (20 March for the first equinox, 21 June for the first solstice, 23 September for the second equinox and 21 December for the last solstice)? I doubt the album would be announced on the 21st of December but it could be released on that day, but an announcement on 23 September this year or 20 March or 21 June next year seems more likely. That said, take this with a large grain of salt. This is purely baseless speculation.