This document summarizes a climate action hackathon hosted by the UNDP CIRDA Programme to develop innovative solutions for sharing weather and climate data to help communities adapt to climate change. The hackathon invited software developers to create apps and tools to bridge the gap in accessing weather information in African countries. Winning prototypes were presented, such as the #mLisho app that communicates rainfall data to farmers to increase forage productivity. The goal was to leverage growing mobile phone access in Africa to provide localized weather warnings and data to vulnerable communities to help guide development and climate change adaptation.