A great resource, for weather, repair, and maintenance
Half of my ride group uses this app for planning what to wear, each time we ride. Particularly the 10,000+ mile per year cyclists. It is easy to see what combination of clothing will keep you warm, from 30F on up, in roughly 5 degree increments. The maintenance section covers tasks from helmet and rider fittings to free hub overhauls. Then you can configure your bike in the app to log your own maintenance.