Integration with the Calendar app

[jancborchardt]

It would be pretty cool if the Weather app would integrate with the Calendar app. That is, in the month or week view show a little icon in the top next to the number of the day of how the weather will be that day. That way you can see a small forecast, directly integrated in your Calendar.

cc @georgehrke @tcitworld @raghunayyar of the Calendar app :)