Rather not risk damaging your phone to write an address or phone number in the rain? Rite in the Rain offers notebooks and writing instruments for outdoor work and activities.
These notepads can withstand being submerged and drenched in liquid, while still holding perfectly legible writings and notes. You can even use them directly in the rain... They're 100% waterproof!
Personally, I use these awesome little notepads for tracking my sites during backpacking trips in the Catskills. Many times I've been caught in horrible storms and needed to jot down my distance or name of the next destination without taking out my phone and risking the damage.
It's always a good idea to carry a small pen and paper with you when you venture outdoors, so better to have ones that are built to last!